Monday, April 5, 2010
Sunday, April 4, 2010
Gastrointestinal System
The topic that I’ll be going discuss is all about gastrointestinal system or so called digestive system. We always wonder how food circulates in our body. In this selection you’ll understand how digestive system works, what are its parts and how does it process.
Digestive system begins with the digestive tract, a muscular tube which contains the organs of digestive system. It has different parts namely mouth, pharynx, esophagus, stomach, small and large intestine, and anus. It also has accessory organs which are liver, salivary glands, gall bladder, pancreas and teeth.
Digestive process starts with the food enters the mouth, ingestion. After ingestion, mastication or the chewing action is the next process. Then, digestion or the chemical process of breaking down the food occurs followed by secretion of acids, buffers, enzyme and water. After that, excretion of waste products and unusable material happens.
The first part of the digestive system is the mouth or buccal cavity which is the opening. It contains lips or labia which is the door to its chamber, tongue that acts as the floor, and tongue base and uvula which is the boundary between oral cavity and next part of digestive system.
The next part is the tongue, a muscle that provides taste, stimuli temperature and texture, it also manipulates food while chewing and aids in swallowing. Salivary glands are 99.4% of water and contain antibodies, buffers, ions, and waste. It has 3 types, the parotid, sublingual, and submandibular.
After that are the teeth. The teeth have 2 categories, the deciduous or baby teeth and permanent teeth. There are different types of teeth, the Incisor which is located at the front and used for cutting, the canine teeth also known as cuspids which holds, tears, and slash the food, the bicuspids which are the transitional teeth, and lastly the molar which is the final teeth used for crushing and grinding the food. It also has three parts, the crown which is the visible part, the neck, and the root. It is composed of dentin, pulp, and cementum.
Next is the pharynx which is already discussed in my previous post. Followed by the pharynx is the esophagus. Esophagus is approximately 10 inches. It transports food from the pharynx to the stomach. It also contains loose layer of connective tissue called adventitia. It has different parts, pharyngoesophageal sphincter and lower esophageal sphincter. Peristalsis is the rhythmic muscular contraction which moves bolus through esophagus.
There are different walls of the alimentary canal. The outermost layer is the serosa. It is composed of a single thin layer of flat serous fluid-producing cells. Next is the muscularis externa which is composed of two layers of smooth muscles. After that is submucosa, it is composed of connective tissue that contains blood vessels and lymph nerve endings. Then the next layer is mucosa, which is composed of two layers of epithelium. Retroperitoneal organs are not surrounded by peritoneum.
After the esophagus is the stomach which is located in the left abdominal cavity under the diaphragm and it is covered almost completely by the liver. It acts as a temporary holding for received foods, secretes gastric acid and enzymes, regulates the rate at which chime enters the small intestine, and absorbs small amount of water and substances. Stomach has four regions: the cardiac region, fundus, body, and pylorus. Gastric juice has different production phases: the cephalic phase, gastric phase, and intestinal phase.
The seventh part is the small intestine that is located in the central lower abdominal cavity. It is the major organ of digestion. It has 3 regions: the duodenum, jejunum, and ileum. There are hormones produced by the small intestine namely secretin which secretes duodenum and stimulates the release of bicarbonate and water. The next hormone is the gastrin which secretes stomach and stimulates the release of gastric juices. Lastly is the cholecystokinin, which stimulates gall bladder.
After the small intestine is the large intestine which reabsorbs water and absorbs vitamin produced by normal bacteria, it also packages and compacts waste products. Like the other parts, it also have regions namely cecum and rectum.
The topic was somehow boring because there were so many discussions. Conrad was the reported so expect an extreme lesson. We had a check up quiz which I passed.
Digestive system begins with the digestive tract, a muscular tube which contains the organs of digestive system. It has different parts namely mouth, pharynx, esophagus, stomach, small and large intestine, and anus. It also has accessory organs which are liver, salivary glands, gall bladder, pancreas and teeth.
Digestive process starts with the food enters the mouth, ingestion. After ingestion, mastication or the chewing action is the next process. Then, digestion or the chemical process of breaking down the food occurs followed by secretion of acids, buffers, enzyme and water. After that, excretion of waste products and unusable material happens.
The first part of the digestive system is the mouth or buccal cavity which is the opening. It contains lips or labia which is the door to its chamber, tongue that acts as the floor, and tongue base and uvula which is the boundary between oral cavity and next part of digestive system.
The next part is the tongue, a muscle that provides taste, stimuli temperature and texture, it also manipulates food while chewing and aids in swallowing. Salivary glands are 99.4% of water and contain antibodies, buffers, ions, and waste. It has 3 types, the parotid, sublingual, and submandibular.
After that are the teeth. The teeth have 2 categories, the deciduous or baby teeth and permanent teeth. There are different types of teeth, the Incisor which is located at the front and used for cutting, the canine teeth also known as cuspids which holds, tears, and slash the food, the bicuspids which are the transitional teeth, and lastly the molar which is the final teeth used for crushing and grinding the food. It also has three parts, the crown which is the visible part, the neck, and the root. It is composed of dentin, pulp, and cementum.
Next is the pharynx which is already discussed in my previous post. Followed by the pharynx is the esophagus. Esophagus is approximately 10 inches. It transports food from the pharynx to the stomach. It also contains loose layer of connective tissue called adventitia. It has different parts, pharyngoesophageal sphincter and lower esophageal sphincter. Peristalsis is the rhythmic muscular contraction which moves bolus through esophagus.
There are different walls of the alimentary canal. The outermost layer is the serosa. It is composed of a single thin layer of flat serous fluid-producing cells. Next is the muscularis externa which is composed of two layers of smooth muscles. After that is submucosa, it is composed of connective tissue that contains blood vessels and lymph nerve endings. Then the next layer is mucosa, which is composed of two layers of epithelium. Retroperitoneal organs are not surrounded by peritoneum.
After the esophagus is the stomach which is located in the left abdominal cavity under the diaphragm and it is covered almost completely by the liver. It acts as a temporary holding for received foods, secretes gastric acid and enzymes, regulates the rate at which chime enters the small intestine, and absorbs small amount of water and substances. Stomach has four regions: the cardiac region, fundus, body, and pylorus. Gastric juice has different production phases: the cephalic phase, gastric phase, and intestinal phase.
The seventh part is the small intestine that is located in the central lower abdominal cavity. It is the major organ of digestion. It has 3 regions: the duodenum, jejunum, and ileum. There are hormones produced by the small intestine namely secretin which secretes duodenum and stimulates the release of bicarbonate and water. The next hormone is the gastrin which secretes stomach and stimulates the release of gastric juices. Lastly is the cholecystokinin, which stimulates gall bladder.
After the small intestine is the large intestine which reabsorbs water and absorbs vitamin produced by normal bacteria, it also packages and compacts waste products. Like the other parts, it also have regions namely cecum and rectum.
The topic was somehow boring because there were so many discussions. Conrad was the reported so expect an extreme lesson. We had a check up quiz which I passed.
Monday, March 29, 2010
Lymphatic System
This article presents basic information about the lymphatic system. This article also explains the functions, anatomy, and components of lymphatic system. I hope you like it.
Lymphatic system is both the transport system and barracks of the immune system it is also the secondary circulatory system. Its functions are recycling the lost fluids from the cardiovascular system and transporting pathogens to the lymph nodes.
Closely connected with the blood and circulatory system, the lymphatic system is an extensive drainage system that returns water and proteins from various tissues back to the bloodstream. It is comprised of a network of ducts, called lymph vessels or lymphatics, and carries lymph, a clear, watery fluid that resembles the plasma of blood. Some scientists consider this system to be part of the blood and circulatory system because lymph comes from blood and returns to blood, and because its vessels are very similar to the veins and capillaries of the blood system. Throughout the body, wherever there are blood vessels, there are lymph vessels, and the two systems work together.
Lymph capillaries are the smallest pipes of the lymphatic system it runs parallel to blood capillaries. Lymph fluid is the fluid filling the lymph capillaries. Lymphatic vessels are where several lymph capillary networks. Lymph nodes are where the largest lymphatic vessels empty.
Lymphatic fluid fills the lymph capillaries that empty to the lymph vessels. Lymph vessels empty into the larger lymphatic vessels that empty to the lymph nodes. Lymph nodes empty lymphatic trunks. Lymphatic trunks empty into one or two collecting ducts that are thoracic duct and right lymphatic duct. Lumbar, intestinal, and intercostals trunks empty into the thoracic duct that empty to the left subclavian vein. Bronchomediastinal, subclavian, and jugular trunks empty into the right lymphatic duct that empty to that right clavian vein.
Innate immunity is the first line of defense against invasion. It is the body’s inborn ability to fight infection and it prevents invasion and infection. It can only recognize but can’t indentify, improve and remember. Adaptive immunity is the back up of the innate immunity. It specifically targets invaders. It can remember, prepare for future action, and can improve responses with experience.
The chemicals that are included in the lymphatic system are cytokinesis, interferon-cytokines, and tumor-necrosis. Cytokinesis is the proteins produced by the damage tissues and WBC that stimulate immune response in a variety of ways. Interferon-cytokines is produced by cells that have been infected by a virus. Tumor-necrosis is a cytokine produced by WBC it stimulates macrophages and also causes cell death in cancer cells.
Leukocytes have two types the polymorphonuclear granulocytes and morphonuclear agranulocytes. Polymorphonulear have four cells: neutrophils, basophils, eosinophils and mast cells. Mononuclear have two types also the monocytes and the lymphocytes. Monocytes have two cells, the macrophages and dandritic cells while lymphocytes have natural killer cells, t lymphocytes, and b lymphocytes.
The lesson was quite easy for me to understand because of a well discussed lecture by my professor. The report did not do very well. I can’t give any appreciation because there were no efforts. It’s good that our professor was always there to clear the indistinct topics. I have studied a lot for this lesson because I actually like it. I got 29/30 items correct.
Lymphatic system is both the transport system and barracks of the immune system it is also the secondary circulatory system. Its functions are recycling the lost fluids from the cardiovascular system and transporting pathogens to the lymph nodes.
Closely connected with the blood and circulatory system, the lymphatic system is an extensive drainage system that returns water and proteins from various tissues back to the bloodstream. It is comprised of a network of ducts, called lymph vessels or lymphatics, and carries lymph, a clear, watery fluid that resembles the plasma of blood. Some scientists consider this system to be part of the blood and circulatory system because lymph comes from blood and returns to blood, and because its vessels are very similar to the veins and capillaries of the blood system. Throughout the body, wherever there are blood vessels, there are lymph vessels, and the two systems work together.
Lymph capillaries are the smallest pipes of the lymphatic system it runs parallel to blood capillaries. Lymph fluid is the fluid filling the lymph capillaries. Lymphatic vessels are where several lymph capillary networks. Lymph nodes are where the largest lymphatic vessels empty.
Lymphatic fluid fills the lymph capillaries that empty to the lymph vessels. Lymph vessels empty into the larger lymphatic vessels that empty to the lymph nodes. Lymph nodes empty lymphatic trunks. Lymphatic trunks empty into one or two collecting ducts that are thoracic duct and right lymphatic duct. Lumbar, intestinal, and intercostals trunks empty into the thoracic duct that empty to the left subclavian vein. Bronchomediastinal, subclavian, and jugular trunks empty into the right lymphatic duct that empty to that right clavian vein.
Innate immunity is the first line of defense against invasion. It is the body’s inborn ability to fight infection and it prevents invasion and infection. It can only recognize but can’t indentify, improve and remember. Adaptive immunity is the back up of the innate immunity. It specifically targets invaders. It can remember, prepare for future action, and can improve responses with experience.
The chemicals that are included in the lymphatic system are cytokinesis, interferon-cytokines, and tumor-necrosis. Cytokinesis is the proteins produced by the damage tissues and WBC that stimulate immune response in a variety of ways. Interferon-cytokines is produced by cells that have been infected by a virus. Tumor-necrosis is a cytokine produced by WBC it stimulates macrophages and also causes cell death in cancer cells.
Leukocytes have two types the polymorphonuclear granulocytes and morphonuclear agranulocytes. Polymorphonulear have four cells: neutrophils, basophils, eosinophils and mast cells. Mononuclear have two types also the monocytes and the lymphocytes. Monocytes have two cells, the macrophages and dandritic cells while lymphocytes have natural killer cells, t lymphocytes, and b lymphocytes.
The lesson was quite easy for me to understand because of a well discussed lecture by my professor. The report did not do very well. I can’t give any appreciation because there were no efforts. It’s good that our professor was always there to clear the indistinct topics. I have studied a lot for this lesson because I actually like it. I got 29/30 items correct.
Respiratory System
The topic that I’m about to discuss is all about the respiratory system. This lesson answers the questions, how do we breathe? How does air comes in and out of the body? And so many more. So as you read this blog may these answer all of your questions.
Respiratory systems primary function is to bring O2 from he atmosphere into h bloodstream and to remove gaseous waste CO2 responsible or providing all o the body’s O2 needs and removing CO2. There are different components of the respiratory system they are two lungs, upper and lower airways, terminal sacs, thoracic cages and muscles.
Breathing is the movement of gas from the atmosphere deep into the lungs. There are two different processes involve in breathing, respiration and ventilation. Respiration is the process of gas exchange in which O2 is added to the blood and CO2 is removed. Ventilation is the bulk movement of the air to the terminal end of the lungs where the actual gas exchange takes place.
Respiration has two type external and internal respiration. External respiration is the gas exchange between the blood and the air while internal respiration is the process of gas exchange where oxygenated blood is transported intentionally via the cardiovascular system to the cells and tissues and CO2 moves into the cells as CO2 is removed.
There are different parts of the respiratory system. These are the bronchi or bronchioles, alveoli, and alveolar. Bronchi and bronchioles are the branching tubes that support the atmosphere gas deep within the lungs. Alveoli are a small air sac, terminal end of the respiratory system. Lastly, alveolar is the combination of alveoli and capillary membrane. It’s where the actual gas exchange takes place.
The upper respiratory tract has different functions. These are heating and cooling inspired gases to the body temperature, filtering particles from inhaled gases, humidifying inspired gasses to a relative humidity 100%, olfaction, phonation, and ventilating the gas down to the lower airways.
The nasal cavity has three main regions. The first region is the vestibular region it is located inside the nostril and contains the vibrissae covered with sebum. The next region is the olfactory region which is located on the roof of the nasal cavity it also keeps inspired gases into the region and does not allow it to reach deeper into the lungs. The last region is the respiratory region which warms and moistens air. It contains turbinates or conchae which are the thee-scroll like bones that split up gases into three channels to provide more surface area. The septal cartilage is the wall separating the two nasal cavities.
Pharynx also called the throat is a hallow muscular structure lived with epithelial tissues. Pharynx has three different sections the nasopharynx, oropharynx, and laryngopharynx. Nasopharynx is the uppermost section of the pharynx. It begins right behind the nasal cavities. It contains lymphatic tissue of the immune system and passageways to the middle ear. The next section is the oropharynx which is located right behind the oral buccal cavity. Anything swallowed passes through this section. It also contains palatines tonsils. The lower most portion of the pharynx is the laryngopharynx which is also called the voice box. It is the semi-rigid composed of cartilage.
The lower respiratory tract refers to the portions of the respiratory system from the trachea to the lungs. The "lower respiratory tract" consists of the lower part of the respiratory system. This consists of the larynx (voice box), trachea (wind pipe), bronchial tubes, bronchioles, and lungs. The larynx is not just our voice box; it also serves as protection for our trachea. The larynx has a flap called the epiglottis which prevents food and water from entering our lungs when we breathe. If the epiglottis does not close when swallowing food or water, there is an involuntary reaction to cough. The larynx also has cilia. The tracheal tube, consists of cartilage, and is the largest tube in the respiratory system. At the bottom of the tube, it branches off into two individual tubes, called the bronchial tubes. The bronchial tubes then branch off into smaller sections inside the lungs called bronchioles. These bronchia’s hold the air sacs in the lungs called the alveoli. The lungs are the biggest organ in the lower respiratory tract. The diaphragm is the main muscle involved for the lungs to breathe and is the largest muscle. There are smaller muscles in between our rib cage that help the lungs expand and contract.
This lesson was not clearly discussed by the reporter because there were no visual aid was used or even presentation. But our professor was able to discuss the lecture clearly. We wrote the lecture written on the board written by our professor. I wasn’t able to answer properly the check up quiz because I didn’t fully understand the report. Overall, the lesson was interesting and educational of course. It’s wonderful to know that there was knowledge shared by the book.
Sunday, February 7, 2010
Cardiovascular System
Wonder how heart pumps blood? How blood is transferred to different parts of your body and how important Cardiovascular System is? Well ill be going to explain this for you.
Cardiovascular system is composed of Heart – the organ that pumps blood through the system, Blood – connective tissue that has plasma and a variety of cells and substances and Blood Vessels – a network of passageways to transport the blood to and from the body’s cells
Blood vessels are intricate networks of tubes that transport blood throughout the entire body. There are different Walls often called coats or tunics. The Tunica interna is the innermost layer, composed of squamous epithelial cells, provide smooth surface so blood can easily pass through. The Tunica media, the middle layer, thicker and are composed of smooth muscles and elastic tissues and collagen. And the Tunica externa which is outermost layer provides vessel support and protection, composed of fibrous tissue.
There are different blood vessels namely Arteries, Aorta, Arteriole, Capillaries, Venules, and Veins. Arteries are an elastic blood vessel that transports blood away from the heart. Aorta is the largest artery in the body, originating from the left ventricle of the heart and extends down to the abdomen, where it branches off into two smaller arteries. Arteriole is a small diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries. Capillaries are where the change of nutrients, gasses and waste products occurs at the cellular level. Venules are ever merging vessels and the tiniest which forms the larger veins. Veins are an elastic blood vessel that transports blood from various regions of the body to the heart. Veins also have thinner walls than arteries, are more numerous, and have a larger capacity to hold blood.
The Heart is a specially shaped muscle that contains series of chambers that move through out the body. The base of the heart is proximal to your head, while the apex is distal. It is a Single organ that acts as a two separate pumps working together. The right side is responsible for collecting the blood and sending it to lungs to pick up oxygen and get rid of carbon dioxide. The left side collects blood from the lungs and pumps it throughout the body.
Pericardium is the fluid filled sac that surrounds the heart and the proximal ends of the aorta, vena cava, and the pulmonary artery. It is divided into three layers: Endocardium is the inner layer of the heart. It consists of epithelial tissue and connective tissue. Myocardium is the muscular middle layer of the wall of the heart. It is composed of spontaneously contracting cardiac muscle fibers which allow the heart to contract. And Visceral Pericardium is the outer layer of the wall of the heart. It is composed of connective tissue covered by epithelium. The epicardium is also known as the visceral pericardium. Pericardial Cavity lies between the visceral pericardium and the parietal pericardium which is filled with pericardial fluid which serves as a shock absorber by reducing friction between the pericardial membranes.
There are different Chambers of the Heart. Atria contains the upper two chambers of the heart are called the left atrium and the right atrium. Ventricle contains the lower two chambers of the heart. The wall that separates the two smaller chambers (atria) is called interatrial septum. The wall that separates the two larger chambers (ventricle) is called interventricular septum.
Vena cava is the two largest veins in the body. They carry de-oxygenated blood from various regions of the body to the right atrium. Superior Vena Cava brings de-oxygenated blood from the head, neck, arm and chest regions of the body to the right atrium. Inferior Vena Cava: brings de-oxygenated blood from the lower body regions to the right atrium.
Heart Valves are flap-like structures that allow blood to flow in one direction. There are different valves, the bicuspid valve, tricuspid valve, aortic valve, and pulmonary valve.
Cardiac cycle is the sequence of events that occur when the heart beats. The cardiac cycle is divided into two: Diastole and Systole. Diastole is part of the cycle which Ventricles are relaxed, Atrioventricular valves are open, The sinoatrial (SA) node, which starts cardiac conduction, contracts causing atrial contraction, the atria empty blood into the ventricles, and Semi lunar valves close preventing back flow into the atria. On the other hand, Systole is part of the cycle which Ventricles contract, atrioventricular valves close and semi lunar valves open. And Blood flows to either the pulmonary artery or aorta.
Autorhytmicity is the unique ability of the cardiac muscles that they don’t rely on nerve impulses and hormones to contract because they can contract on their own. Step 1: Pacemaker Impulse Generation - SA node contracts generating nerve impulses. Step 2: AV Node Impulse Conduction - Impulses are delayed for about tenth of a second this allows the atria to contract and empty their contents first. Step 3: AV bundle Impulse Conduction - The bundles branches off into two and the impulses are carried down the center of the heart to the left and right ventricle. Step 4: Purkinje Fibres Impulse conduction- AV bundles divides into Purkinje fibres in the ventricles to contract
The function of the Blood is to transports dissolved gases, Waste products of metabolism, Hormones; Enzymes; Nutrients , Plasma proteins, Blood cells (incl. white blood cells 'leucocytes', and red blood cells 'erythrocytes'), maintain Body Temperature, control, remove toxins from the body, regulate Body Fluid Electrolytes, help to protect us from the invasion and infection by pathogens and toxins.
Erythrocytes (Red blood Cells) RBCs are created by the red bone marrow through a process called hemopoiesis. It performs two crucial functions: transports oxygen from the lungs to the cells in the body with the aid of an iron-containing red pigment called haemoglobin and help to transport carbon dioxide, a by-product of cellular metabolism, from the cells to the lungs for removal from the body.
Leukocytes (White blood Cells) WBCs are guardians from invasion and infection. The types of WBC’s are Polymorphonuclear granulocyte and Agranulocyte. Polymorphonuclear granulocyte composes Neutrophils, Basophils and Eosinophils. Agranulocyte composes of Monocytes and Lymphocytes.
Thrombocytes (Blood Platelets) are the smallest formed elements. It is responsible for the bloods ability to clot and it releases serotonin which can cause smooth muscle constriction and decreased blood flow.
Cardiovascular system is composed of Heart – the organ that pumps blood through the system, Blood – connective tissue that has plasma and a variety of cells and substances and Blood Vessels – a network of passageways to transport the blood to and from the body’s cells
Blood vessels are intricate networks of tubes that transport blood throughout the entire body. There are different Walls often called coats or tunics. The Tunica interna is the innermost layer, composed of squamous epithelial cells, provide smooth surface so blood can easily pass through. The Tunica media, the middle layer, thicker and are composed of smooth muscles and elastic tissues and collagen. And the Tunica externa which is outermost layer provides vessel support and protection, composed of fibrous tissue.
There are different blood vessels namely Arteries, Aorta, Arteriole, Capillaries, Venules, and Veins. Arteries are an elastic blood vessel that transports blood away from the heart. Aorta is the largest artery in the body, originating from the left ventricle of the heart and extends down to the abdomen, where it branches off into two smaller arteries. Arteriole is a small diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries. Capillaries are where the change of nutrients, gasses and waste products occurs at the cellular level. Venules are ever merging vessels and the tiniest which forms the larger veins. Veins are an elastic blood vessel that transports blood from various regions of the body to the heart. Veins also have thinner walls than arteries, are more numerous, and have a larger capacity to hold blood.
The Heart is a specially shaped muscle that contains series of chambers that move through out the body. The base of the heart is proximal to your head, while the apex is distal. It is a Single organ that acts as a two separate pumps working together. The right side is responsible for collecting the blood and sending it to lungs to pick up oxygen and get rid of carbon dioxide. The left side collects blood from the lungs and pumps it throughout the body.
Pericardium is the fluid filled sac that surrounds the heart and the proximal ends of the aorta, vena cava, and the pulmonary artery. It is divided into three layers: Endocardium is the inner layer of the heart. It consists of epithelial tissue and connective tissue. Myocardium is the muscular middle layer of the wall of the heart. It is composed of spontaneously contracting cardiac muscle fibers which allow the heart to contract. And Visceral Pericardium is the outer layer of the wall of the heart. It is composed of connective tissue covered by epithelium. The epicardium is also known as the visceral pericardium. Pericardial Cavity lies between the visceral pericardium and the parietal pericardium which is filled with pericardial fluid which serves as a shock absorber by reducing friction between the pericardial membranes.
There are different Chambers of the Heart. Atria contains the upper two chambers of the heart are called the left atrium and the right atrium. Ventricle contains the lower two chambers of the heart. The wall that separates the two smaller chambers (atria) is called interatrial septum. The wall that separates the two larger chambers (ventricle) is called interventricular septum.
Vena cava is the two largest veins in the body. They carry de-oxygenated blood from various regions of the body to the right atrium. Superior Vena Cava brings de-oxygenated blood from the head, neck, arm and chest regions of the body to the right atrium. Inferior Vena Cava: brings de-oxygenated blood from the lower body regions to the right atrium.
Heart Valves are flap-like structures that allow blood to flow in one direction. There are different valves, the bicuspid valve, tricuspid valve, aortic valve, and pulmonary valve.
Cardiac cycle is the sequence of events that occur when the heart beats. The cardiac cycle is divided into two: Diastole and Systole. Diastole is part of the cycle which Ventricles are relaxed, Atrioventricular valves are open, The sinoatrial (SA) node, which starts cardiac conduction, contracts causing atrial contraction, the atria empty blood into the ventricles, and Semi lunar valves close preventing back flow into the atria. On the other hand, Systole is part of the cycle which Ventricles contract, atrioventricular valves close and semi lunar valves open. And Blood flows to either the pulmonary artery or aorta.
Autorhytmicity is the unique ability of the cardiac muscles that they don’t rely on nerve impulses and hormones to contract because they can contract on their own. Step 1: Pacemaker Impulse Generation - SA node contracts generating nerve impulses. Step 2: AV Node Impulse Conduction - Impulses are delayed for about tenth of a second this allows the atria to contract and empty their contents first. Step 3: AV bundle Impulse Conduction - The bundles branches off into two and the impulses are carried down the center of the heart to the left and right ventricle. Step 4: Purkinje Fibres Impulse conduction- AV bundles divides into Purkinje fibres in the ventricles to contract
The function of the Blood is to transports dissolved gases, Waste products of metabolism, Hormones; Enzymes; Nutrients , Plasma proteins, Blood cells (incl. white blood cells 'leucocytes', and red blood cells 'erythrocytes'), maintain Body Temperature, control, remove toxins from the body, regulate Body Fluid Electrolytes, help to protect us from the invasion and infection by pathogens and toxins.
Erythrocytes (Red blood Cells) RBCs are created by the red bone marrow through a process called hemopoiesis. It performs two crucial functions: transports oxygen from the lungs to the cells in the body with the aid of an iron-containing red pigment called haemoglobin and help to transport carbon dioxide, a by-product of cellular metabolism, from the cells to the lungs for removal from the body.
Leukocytes (White blood Cells) WBCs are guardians from invasion and infection. The types of WBC’s are Polymorphonuclear granulocyte and Agranulocyte. Polymorphonuclear granulocyte composes Neutrophils, Basophils and Eosinophils. Agranulocyte composes of Monocytes and Lymphocytes.
Thrombocytes (Blood Platelets) are the smallest formed elements. It is responsible for the bloods ability to clot and it releases serotonin which can cause smooth muscle constriction and decreased blood flow.
Special Senses
Everything we know about the world comes to us through our senses. Usually, we were thought to have just five of them—sight, hearing, touch, smell, and taste. Scientists now recognize that we have several additional kinds of sensations, such as pain, pressure, temperature, joint position, muscle sense, and movement, but these are generally included under "touch."
The first sense that ill be going to discuss is the Eye. There are External structures of the eye. Lacrimal apparatus includes a series of ducts and the lacrimal glands that produce tears, which washes and lubricates the eyeball. Eyelids protect the eyes associated with eyelids that prevent gross particles to enter the eye. The conjunctiva is a mucous membrane that covers the anterior eyeball and lines the eyelids. The sclera is the outer, tough, protective layer. Its anterior portion is the cornea, which is transparent to allow light to enter the eye. The choroid is the middle layer, which provides nutrition to the internal eye structures and prevents light's scattering in the eye. Anterior modifications include the iris which controls the size of the pupil). The retina is the innermost layer, which contains the photo pigments. Rods are dim light receptors. Cones are receptors that provide for colour vision and high visual acuity. The fovea centralis, on which acute focusing occurs contains only cones. The blind spot (optic disk) is the point where the optic nerve leaves the back of the eyeball. The lens shape is changed by the ciliary muscle for close focus. Anterior to the lens is the aqueous humour; posterior to the lens is the vitreous humour. Both humours reinforce the eye internally. The aqueous humour also provides nutrients to the lens and cornea. Errors of refraction include myopia, hyperopia, and astigmatism. All are correctable with specially ground lenses.
Next to be discussed is the sense of hearing. The ear is divided into three major areas. Outer ear structures are the pinna (auricle), external auditory canal, and tympanic membrane (eardrum). Sound entering the external auditory canal sets the eardrum into vibration. Middle ear structures are the ossicles and auditory tube within the tympanic cavity. The ossicles are malleus, incus, and stapes which transmit the vibratory motion from the eardrum to the oval window. The auditory tube allows pressure to be equalized on both sides of the eardrum. These structures are also involved with sound transmission only. Inner ear, or bony labyrinth, consists of bony chambers namely cochlea, vestibule, and semicircular canals in the temporal bone. The bony labyrinth contains perilymph and membranous sacs filled with endolymph. Within the membranous sacs of the vestibule and semicircular canals are equilibrium receptors. Hearing receptors are found within the membranes of the cochlea. The organ of Corti is receptor for hearing within the cochlea it is stimulated by sound vibrations transmitted through air, membranes, and fluids. Deafness is any degree of hearing loss. Conduction deafness results when the transmission of sound vibrations through the external and middle ears is hindered. Sensorineural deafness occurs when there is damage to the nervous system structures involved in hearing.
Lastly to talk about is the sense of smell and taste. The olfactory (smell) receptors are located in the superior aspect of each nasal cavity. Sniffing helps you to bring more air (containing odours) over the olfactory mucosa. Olfactory pathways are closely linked to the limbic system; odours recall memories and arouse emotional responses. Gustatory (taste) cells are located in the taste buds, primarily on the tongue. The four major taste sensations are sweet, salt, sour, bitter. Taste and appreciation of foods is influenced by the sense of smell and the temperature and texture of foods.
All throughout the reporting, the lesson was clearly discussed by the reporter and my professor. The reporter did a good job in preparing his visual aids. Our teacher gave us an activity in which we have to draw the anatomy of the eye which I enjoyed a lot because I’m somehow good in drawing .
The first sense that ill be going to discuss is the Eye. There are External structures of the eye. Lacrimal apparatus includes a series of ducts and the lacrimal glands that produce tears, which washes and lubricates the eyeball. Eyelids protect the eyes associated with eyelids that prevent gross particles to enter the eye. The conjunctiva is a mucous membrane that covers the anterior eyeball and lines the eyelids. The sclera is the outer, tough, protective layer. Its anterior portion is the cornea, which is transparent to allow light to enter the eye. The choroid is the middle layer, which provides nutrition to the internal eye structures and prevents light's scattering in the eye. Anterior modifications include the iris which controls the size of the pupil). The retina is the innermost layer, which contains the photo pigments. Rods are dim light receptors. Cones are receptors that provide for colour vision and high visual acuity. The fovea centralis, on which acute focusing occurs contains only cones. The blind spot (optic disk) is the point where the optic nerve leaves the back of the eyeball. The lens shape is changed by the ciliary muscle for close focus. Anterior to the lens is the aqueous humour; posterior to the lens is the vitreous humour. Both humours reinforce the eye internally. The aqueous humour also provides nutrients to the lens and cornea. Errors of refraction include myopia, hyperopia, and astigmatism. All are correctable with specially ground lenses.
Next to be discussed is the sense of hearing. The ear is divided into three major areas. Outer ear structures are the pinna (auricle), external auditory canal, and tympanic membrane (eardrum). Sound entering the external auditory canal sets the eardrum into vibration. Middle ear structures are the ossicles and auditory tube within the tympanic cavity. The ossicles are malleus, incus, and stapes which transmit the vibratory motion from the eardrum to the oval window. The auditory tube allows pressure to be equalized on both sides of the eardrum. These structures are also involved with sound transmission only. Inner ear, or bony labyrinth, consists of bony chambers namely cochlea, vestibule, and semicircular canals in the temporal bone. The bony labyrinth contains perilymph and membranous sacs filled with endolymph. Within the membranous sacs of the vestibule and semicircular canals are equilibrium receptors. Hearing receptors are found within the membranes of the cochlea. The organ of Corti is receptor for hearing within the cochlea it is stimulated by sound vibrations transmitted through air, membranes, and fluids. Deafness is any degree of hearing loss. Conduction deafness results when the transmission of sound vibrations through the external and middle ears is hindered. Sensorineural deafness occurs when there is damage to the nervous system structures involved in hearing.
Lastly to talk about is the sense of smell and taste. The olfactory (smell) receptors are located in the superior aspect of each nasal cavity. Sniffing helps you to bring more air (containing odours) over the olfactory mucosa. Olfactory pathways are closely linked to the limbic system; odours recall memories and arouse emotional responses. Gustatory (taste) cells are located in the taste buds, primarily on the tongue. The four major taste sensations are sweet, salt, sour, bitter. Taste and appreciation of foods is influenced by the sense of smell and the temperature and texture of foods.
All throughout the reporting, the lesson was clearly discussed by the reporter and my professor. The reporter did a good job in preparing his visual aids. Our teacher gave us an activity in which we have to draw the anatomy of the eye which I enjoyed a lot because I’m somehow good in drawing .
Monday, January 11, 2010
Endocrine System
Our first topic this third grading was endocrine system. I don’t know so much about endocrine system but I’ve heard of it as the body’s other control center. So, here’s a short summary of what I have learned. Hope you’ll enjoy it .
Endocrine system is a series of organs and glands in your body. It secretes chemical messengers called hormone into your bloodstream.
Hormones are chemical messengers released by endocrine glands, it is also released into the bloodstream and travel all over your body, it can affect million of cells simultaneously, and their effects last for minutes or even hours or days.
Neurotransmitters are released by neurons at chemical synapses, it diffuses across the synapse to a cell on the other side and bind to that cell, it cleaned up quickly and its effects are localized and short lived.
There are different endocrine organ functions namely, hypothalamus, pineal, pituitary, thyroid, parathyroid, pancreas, adrenal glands, and ovaries and testes.
The hypothalamus is located in the lower central part of the brain. This part of the brain is important in regulation of satiety, metabolism, and body temperature. In addition, it secretes hormones that stimulate or suppress the release of hormones in the pituitary gland.
The pineal body, or pineal gland, is located in the middle of the brain. It secretes a hormone called melatonin, which may help regulate the wake-sleep cycle of the body.
The pituitary gland is divided into two parts: the anterior lobe and the posterior lobe. The anterior lobe produces the following hormones, which are regulated by the hypothalamus: Growth hormone which stimulates growth of bone and tissue (growth hormone deficiency in children results in growth failure. Thyroid-stimulating hormone (TSH) which stimulates the thyroid gland to produce thyroid hormones.
Adrenocorticotropin hormone (ACTH) which stimulates the adrenal gland to produce several related steroid hormones. Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are hormones that control sexual function and production of the sex steroids, estrogen and progesterone in females or testosterone in males. Prolactin is a hormone that stimulates milk production in females. The posterior lobe produces the following: Antidiuretic hormone (vasopressin) controls water loss by the kidneys and Oxytocin which contracts the uterus during childbirth and stimulates milk production.
The thyroid gland is located in the lower front part of the neck. Thyroid gland secretes hormones thyroxine and triiodothyroxine which controls cell metabolism and growth and also calcitonin which decreases blood calcium.
The parathyroid glands are two pairs of small glands fixed in the surface of the thyroid gland, one pair on each side. They release parathyroid hormone, which regulates and increase calcium levels in the blood and bone metabolism.
The endocrine pancreas secretes hormones called insulin and glucagon. These hormones regulate the level of glucose (sugar) in the blood. Insulin lowers blood sugar while glucagon raises blood sugar.
The adrenal glands are a pair of small glands that sit on top of your kidney. The adrenal glands are made up of two parts. The outer part is called the adrenal cortex, and the inner part is called the adrenal medulla. The inner part releases two hormones called epinephrine and norepinephrine which increase the duration of the effects of your sympathetic nervous system. On the other hand, the outer part makes dozens of steroid hormone known as adrenocorticosteroids.
The reproductive glands in males, the testes, located in the scrotum, secrete hormones called androgens; the most important of which is testosterone. These hormones affect many male characteristics as well as sperm production. In females, the ovaries, located on both sides of the uterus, produce estrogen and progesterone as well as eggs. These hormones control the development of female characteristics and they are also involved in reproductive functions.
This chapter was kind of unclear because it was discussed by the reporter before our vacation that’s why some of it I don’t remember already. The words are hard to remember because of its spelling too. I got low grade in the check up quiz that’s why I feel bad. Anyway, our professor did made the chapter clear so in the end it was still ok.
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