Nervou System Part I

This week we discussed about nervous system which is soooo long! Here is what I have learned! Down there! 


Nervous system is divided into two: central nervous system which is responsible for the brain and spinal cord and Peripheral nervous system which is responsible for the nerve outside the brain and spinal cord. Peripheral nervous system has somatic (skeletal muscles) and autonomic (smooth and cardiac muscle and gland). Autonomic can be parasympathetic (homeostasis) and sympathetic (alert system).

We also talked about nervous tissues. Neuroglia or glia cells are specialized cell that allows nervous system to perform its functions. In CNS there are 4 tissues: Astrocytes which are metabolic and structural support cells, Microglia which removes the debris, Ependymal cells which covers the lining cavities and the Oligodendrocytes which makes the myelin. While in PNS there are 2 tissues: Schwann cells which makes the myelin and Satellite cells which are the support cells.



I have learned that Neurons are the control function of nervous system and there are the ones responsible for measuring environment and making decisions. Dendrites are a part of neuron that receives the information from other cells. Axon is also a part of neuron that generates and sends signals to other cells. Axon terminal is the connection to a receiving cell. The combination of axon terminal and receiving cell is what we call synapse. Neurons can be classified by its structure and function. By its structure, bipolar, multipolar and unipolar while by function, sensory neurons, motor neurons, and interneurons. Excitable cells are also neurons; it carries a small electric charge when stimulated. It is the reason why electrocution can cause nervous system damage. It shorts out the electrical pathways in the neurons.

The reporter also discussed about action potentials. Action potentials are the whole series of permeability changes within the cell and the resultant changes of in the internal and external changes to carry the impulse down the axon. If the cell is not stimulated it is polarize. If the cell is more positive than resting it is depolarize. Hyperpolarized is the cell that overshoots and becomes more negative when at rest. The period during which action potentials cannot accept another stimulus is what we call refractory period.

The size of the stimulus determines the excitement of the cell. A big stimulus causes a bigger depolarization than a small stimulus.

Impulse conduction happens once an action potential is formed; it travels down the axon from the cell body to the terminal. It has two characteristics: presence of myelin and diameter of axon. Myelin is lipid insulation or a sheath. When an axon is wrapped with myelin it is called myelinated which look white while unmyelinated looks gray. The diameter of axon affects the speed of action potential flow.

Spinal cord is located in a hallow tube running inside the vertebral column from the foramen magnum to the second lumbar. Meninges are series of protective membranes surrounding the brain; it covers the delicate structure of the brain and spinal cord, and helps to set up a layer that acts as a cushioning and shock absorbers. It has 3 layers: dura mater, arachnoid mater, and pia mater. It also has spaces: epidural space which is the space between dura and vertebral column, subdural space the space between dura mater and arachnoid mater, and subarachnoid space the soace between arachnoid and pia mater.




Spinal cord contains fissure and sulcus. Sulcus is a shallow groove in the CNS surface while fissure is a deep grove on the CNS also. Sulcus has different sections horns where neurons have their cell bodies and columns which act as nerve tract, pathway, or axon running up and down the spinal cord to and from the brain.

Nerves are the connection between the CNS and the world outside the CNS. Spinal nerves are nerves that are connected to the spinal cord. Mixed nerve is a nerve that carries both type of information. The complex branching patterns of nerves are plexuses.

Reflexes are the simplest form of motor output. Its response is proportionate to the stimulus. There are 3 types of reflexes: withdrawal reflexes which are an activated, vestibular reflex which keeps you vertical, and startle reflexes which cause you to jump at loud sounds.

This was a long chapter. It takes days for me to fully understand the lesson. The reporter did put effort on the visual aids but she wasn’t able to discuss it properly. She simply doesn’t know some of her report that’s why we didn’t understand it well.

Integumentary System

This week our lesson was the integumentary system. As stated in the report Integumentary system is comprised of the skin; accessory composed of hair, nails and associated glands, protects an invasion of disease-protecting pathogens, helps keep body from drying out, produces vitamin D, and helps regulate body temperature.

Skin as we all know is the largest organ which covers area about 20.83 sq. ft. of an adult body.

There are 3 layers of the skin epidermis, dermis, and subcutaneous fascia or hypodermis.

Epidermis is made up of five or six even smaller layers of stratified squamous epithelium. It is avascular – contains no blood vessels or nerve cells. It is the outermost layer of the skin which is dead cells – stratum corneum. Where do we get our skin colour? Melanocytes are specialized cells which are responsible for skin colour and produces melanin – actual substance that affects the skin colour. Carotene is another pigment which gives the yellowish hue to the skin.

Dermis is inferior to epidermis layer. It is sometimes called corium – thickest layer. It is a layer of dense, irregular, connective tissue. Dermis is considered as the true skin. It contains capillaries, collagenous and elastic fibres which helps movement, involuntary muscle, nerve endings, lymph vessels which transports fluid from tissue to the blood system, hair follicle, sebaceous glands (oil) which keep the skin form drying out, and sudoriferous glands (sweat) which has two types apocrine which can be found in groin region, anal region, and armpits and eccrine which is located all over the body.

Subcutaneous fascia is the innermost layer of the skin. It is composed of elastic and fibrous tissue, fatty tissue, and lipocytes. These are the ones attached to the muscle of the body.

There are 4 burns of the skin first up to fourth degree burn. When the damage is only the epidermis it is considered as first degree burn. If it involves the entire depth of epidermis and a portion of dermis it is said to be the second degree burn. Third degree burn affects all the 3 layers of the skin. When burn penetrates to the bone it is said to be fourth degree burn.

Nails are specialized epithelial cells originating from nail root. Nails are keratinized or hardened protein. Cuticle is a fold of tissue that covers the nail root. Nail body is the portion that we see. The pink colour of the skin is caused by the vascularisation of tissue under the nails. Lunula is the half moon shaped area.

Hair helps to regulate body temperature. It is composed of keratin-fibrous tissue. The hair that you can see is what we called shaft. Follicles are formed by epithelial cells which have rich source of blood. It also contains sebaceous glands which secrets sebum – oily substance that coast the follicle and works its way to the skin surface,

There are different common disorders of integumentary system. Lesion is a pathologically altered piece of tissue that includes a wound or injury or a single infected patch of skin. Some other disorders are Abrasion, Acne, Athlete’s foot, Bed sores, Boil, Cold sore, Eczema, Hires, Scabies and so many more.

This Report was ok. I learned well. I understand everything. My questions were answered correctly well, I’m happy about that. I wished there could be some other way to report other than having ppt. slides. What else could be? Hmmmm,  I don’t know how to report also. We didn’t have any activity regarding this topic. There was a test which I was the highest (chin up* raised eyebrows*)  our professor just gave us a review quiz which is I’m not sure if I passed. Well nice effort reporter.

Wonder how hot boys have those great yummy (uuhhhmmm) muscles?? LOL!. Wonder how those muscles get bigger? Wonder why it attract….ssss us?
Eeeeeeeerrrrrrrrrrrrr! Yes I should stop before I say something horrible, you know what I mean >.>. So, this blog is not about those silly boys, its about muscular system. I just made a sexy introduction so I’d get your attention. READ IT TIL THE END. Ok?!


As I listen to the reporter I knew what muscles are, there are the general term for contractile tissue. Muscular system allows an alternate contraction and relaxation which causes movement. Muscles cells are elongated fibres.

There are three major types of muscles: skeletal, smooth, and cardiac muscles. Skeletal muscles are under conscious which means they are voluntary and are attached to the bones. The fibres in this muscles are striated, means stripped muscles. Skeletal muscles also allow movements. Unlike skeletal, smooth muscles are not under conscious control which means involuntary, it doesn’t have the striped appearance of skeletal muscles, it is the muscle of organs or sometimes called visceral muscles, and it facilitates the movement of blood. The last type is the cardiac muscle which can be found in the heart obviously, it has striated appearance but involuntary, and it makes up the walls of the heart and causes it to contract.

In this lesson the reporter also discussed movement as it relates to muscles. For example, Rotation describes circular movement; Abduction means to move away from the body; Adduction occurs when you produce a movement towards the body; Extension is used for increasing the angle between two bones, while Flexion is the opposite.

The reporter also explored the makeup of the muscle fibres to let us know how contraction works does. Muscles consist of elongated cells called muscles fibres. Each muscle fibre contains myofibrils, and these myofibrils are bundled together to form a muscle cell. Contraction rakes place from functional contractile units called sarcomeres. Sacromeres has two types of threadlike structure called thick and thin myofilaments. Thick myofilaments are composed of protein myosin, and the thin ones are composed of protein actin. The striated appearance of the muscles is called Z-lines.

There are common disorders occurring the muscular system. Here re just few examples: Fibromyalgia, Myalgia, Ataxia, Paralysis, Spasm or Cramps, Sprains, Hernia, Tendinitis, Myasthenia gravis and so many more.

I’d like to comment about the way this was reported. Such a mess, no visual aids or something that can make a listener get interested in the discussion. I wasn’t able to understand the lecture so I have to read it by my own. (WTH) I got mad because we had a quiz which I’m not ready to take because of not knowing what the reporter is saying in front of me. >,< grr!

Skeletal System

The lesson that ill be going to discuss is all about skeletal system. When we hear skeletal system we usually think about bones. Do you? Cause I do. Just so you know skeletal system is the framework of human body, it produces blood cells, provides protection to our organs, helps us to breathe, stores minerals, and allows movement along with muscular system.

Skeletal system’s primary components are bones. Bones are composed of non-living minerals such as calcium. There are different classifications of bones: long bones which can be found in arms and legs, short bones which can be found in wrists and ankles, flat bones which can be found in the skull, ribs, and breast bone, and Irregular bones which can be found in the hip and vertebrae that makes up the spine.

There are also different parts of a bone. Periosteum which covers the bone, Epiphysis which is each bone end, Diaphysis which is the region between the ends, medullar cavity which is a hollow region that acts as a storage area for bone marrow, and bone marrow which has two types: yellow which has a high fat content and red which is in charge for production of red blood cells.

There are different types of bone tissues: compact and spongy or cancellous tissues. Compact tissue is a dense hard tissue that is composes of shafts of long bones and outer layer of bones. Spongy or cancellous tissue which is arrange in bars and plates called trabeculae, it is also lined with endosteum-a tissue similar to periosteum, it helps to make the bones lighter in weight.

Bones have a projection which is the points of attachment, bumps and depressions which are the pathways for nerves and blood vessels.

Wonder how bones are formed? Bones are formed through Ossification. Bone grows longitudinally in order to develop height and horizontally so they can more efficiently support body weight. There are different cells involved in ossification. Osteoprogenitor cells are non-specialized cells found in periosteum, endosteum and central canal. Oeseoblasts are cells that actually form bones. Osteocytes are the mature cells. Lastly, Osteoclasts originated form a type of white cell called monoocyte that is found in red bone marrow. Intramembraneous ossification occurs when bone develops between two sheets compose of fibrous connective tissue. Endochondral ossification occurs when shaped cartilage is replaced by bone.

Cartilage is a special form of connective tissue that can withstand a fair amount of flexing, tension and pressure. These are the ones which makes a flexible connection between bones, it acts as a cushion between the bones Articular cartilage acts as a shock absorber it is located at the ends of the bones. Bursa is a small sack that contains a synovial fluid.

When two or more bones are joined together they are called Joints. Joints are classified into two: function and structure. Classification of bones according to function are immobile, slightly movable, and freely moving. While according to structure are fibrous, cartillagenous, and synovial joint.

Actually, we had this discussed only for an hour. So it was hard for me to comprehend it well because the reporter should make the discussion fast because she’ll run out of time. The reporter only had a one hour limit to report. It was really hard to be familiar with the discussion for a short period of time. I’d say it is “boring” because the reporter was only reading her slides, (it was 40+ slides I guess >.>) even though I appreciated her effort. If the reporter made it short and used simple graphs I would possibly enjoyed her discussion. I liked it when our professor gave us an activity in which we have to make a skeleton dance. The whole class participated in this activity and so it was fun like everyone was laughing at each others faces and the way they dance. It is good to have an activity like this after a long discussion. Well, professors really do know how to make his students look stupid in front of the class.