DIGESTIVE SYSTEM

Digestive tract ( often called the alimentary canal ) is a muscular tube or tunnel- like structure which contains the organs of the digestive system. This tube begins at the mouth and ends at the anus. Between these two points are the pharynx, esophagus, stomach, and small and large intestines. In addition, accessory organs such as teeth, salivary glands, liver, gall bladder and pancreas are necessary for processing materials into usable substances.

STEPS PERFORMED BY THE DIGESTIVE PROCESS:

1. INGESTION - food enters the mouth
2. MASTICATION - chewing action ( mechanically process, physically breaks down )
3. DIGESTION - chemical process of breaking down food
4. SECRETION - includes acids, buffers, enzymes and water
5. ABSORPTION - through the lining of the digestive tract use by the body
6. EXCRETION ( DEFECATION ) - waste products and unusable materials


1.MOUTH AND ORAL CAVITY
Mouth is the opening that leads to the oral cavity, which is also called buccal cavity. Your lips or labia, act as a door to this chamber. The hard and soft palates create the roof of the chamber, while the tongue acts as the floor.





2. TONGUE
Tongue is a muscle that performs many duties. It provides taste stimuli to your brain, senses temperature and texture, manipulates food while chewing and aids in swallowing. The tongue pushes the food into a ball- like mass called bolus so it can be passed on to the pharynx. A membrane under your tongue, called lingual frenulum, which you can see when you lift up your tongue.




3. SALIVARY GLAND
There are three pairs of salivary glands, which are controlled by the autonomic nervous system. The parotid is found slightly inferior and anterior to the each ear. The ones that swell up when you got the mumps. The smallest salivary glands, the sublingual, are located under the toungue. The submandibular are located on both sides along the inner surface of the mandible, or lower jaw.





4. TEETH
The final important components of the mechanical aspect of digestion in the oral cavity are the teeth. It is unfortunate that we get only two sets of them in a lifetime. The first set of teeth are called decidous teeth, or known as " baby teeth. " It appear at around 6 months of age. Between the ages of 6 and 12 years the Tooth Fairy is kept busy as these teth are pushed out and replaced by the 32 larger permanent teeth.

".,LYMPHATIC AND IMMUNE SYSTEM,."

The lymphatic system is both the transport system and barracks of your immune system. It is a second circulatory system parallel to the cardiovascular system.

The lymphatic system has four functions:
* storage and maturation of some types of white blood cells
*recycling of lost fluids from the cardiovascular system
*absorption of glycerol and fatty acids from food
*transporting pathogens to the lymph nodes.

Given that the lymphatic system is intimately connected to the function of cardiovascular system, it should come no surprise that the smallest pipes of the lymphatic system, called lymph capillaries, run parallel to blood capillaries. The fluid filling the lymph capillaries is called lymphatic fluid, or simply lymph. The lymphatic vessels is where several lymph capillary networks. Structurally similar veins, including valves. The lymph nodes is where the larges lymphatic vessels empty.

Lymphatic vessels exiting lymph nodes empty into one of several lymphatic trunks.These trunks, named for their locations, are lumbar, intestinal, bronchomediastinal, subclavian, jugular and intercostal. There are two larger collections of lymphatic tissue, known as lymph organs. These lymph organs are the thymus and the spleen. The spleen is a spongy organ and has blood sinuses. Surrounded by the blood sinuses are islands of white pulp containing lymphocytes and islands of red pulp. The thymus is a soft organ. It is bigger in the children and becomes smaller or even disappears in adults. The thymus is packed with lymphocyte.

The immune system defends the body on two fronts, by innate and adaptive. Innate immunity is the first line of defense against invasion while the adaptive immunity is the back up.

COMPONENTS OF THE IMMUNE SYSTEM

BARRIER : Anything that prevents invaders from getting inside your body prevents infection. Your body has many barriers located in the places where invaders are most likely to gain entrance. Physical barrier include skin and mucous membranes of the eyes, digestive system, respiratory, and reproductive system. The fluids associated with these chemicals are contain chemicals that act as chemical barriers. These chemicals are contained in tears, saliva, urine, mucous secretion, and sweat.

CELLS : White blood cells ( leukocytes ) are responsible for defending the body against invaders. Red blood cells are responsible for carrying oxygen throughout the body. And platelets are responsible for blood's ability to clot. The immune system uses a dozen or more different types of cells to combat pathogens. All of these cells are leukocytes or modified leukocytes. Leukocytes can be divided into two groups. Polymorphonuclear granulocytes are cells with granules or spots in their cytoplasm. Agranulocytes or mononuclear cells have no granulocytes in their cytoplasm. These two groups contains several different types of cells that play a role in the body's defense against infection.

*POLYMURPHONUCLEAR GRANULOCYTES

** NEUTROPHILS
- whose function is phagocytosis
- most common leukocytes in the blood stream
- originate in the bone marrow
- release chemical that increase tissue damage of inflammation
- part of innate immunity

** BASOPHILS
- release chemicals to promote inflammation
- mobile, entering infected tissues from the bloodstream
- low in number

**MAST CELLS
- not mobile
- found stationed throughout the body
- also found in connective tissue

**EOSINOPHILS
- counteract the activities of basophils and mast cells
- break down the chemicals released by basophils and mast cells
- also have role in fighting invasion by parasitic worms


*MONONUCLEAR ( AGRANULOCYTES )
** MONOCYTES
> MACROPHAGES
- modified monocytes
- phagocytic cells, which are active in the later stages of an infection
- release chemicals to stimulate the immune system

>DENDRITIC CELLS
- weakly phogocytic
- most important job is as antigen displaying cells or ADC's
- able to ingest a foreign cell and place the foreign antigens into their own membrane

**LYMPHOCYTES
>NATURAL KILLER CELLS
- kills any cells displaying foreign bodies part of innate immunity
-early symptoms of a cold or flu are due to the action of NK cells

>T- LYMPHOCYTES ( T- CELLS )
- responsible for a portion of adaptive immunity known as cell- mediated immunity
- TYPES:
= CYTOTOXIC T CELLS ( CELL POISON )
- kills infected cells and release immune stimulating chemicals

= HELPER T CELLS
- help activate other parts of adaptive immunity

= REGULATORY T CELLS
- regulate immune response

= MEMORY T CELLS
- remember pathogens after exposure

>B LYMPHOCYTES ( B- CELLS )
- known as antibody- mediated immunity
- TYPES:
= PLASMA CELLS
- produce antibodies to nonself-antigens

= MEMORY B CELLS
- remember pathogens

.VIDEO-REGIONS OF THE SMALL INTESTINE!!!!!@_@.

* rESpiRatOrY SysTeM *

The respiratory system is responsible for providing oxygen for the blood to take to the body's tissues and removing carbon dioxide, one of the waste products of cellular metabolism. The respiratory system is closely interrelated with the heart and circulatory system. These two systems can be grouped together in medicine to form the cardiopulmonary system.

The respiratory system consists of the following:
* Two lungs, the vital organs of the respiratory system.
*Upper and lower airways
*Terminal air sacs called alveoli
*Thoracic cage
*Muscles of breathing

There are two separate processes of breathing. The first is ventilation, which is the bulk movement of the air down to the terminal end of the lungs where the actual gas exchange takes place with the bloodstream. The second is respiratory, which is the process of gas exchange where oxygen is added to the blood and carbon dioxide is removed. Since the gas exchange in the lungs occur between the blood and the air in the external atmosphere, it is called external respiration. The oxygenated blood is transported internally via the cardiovascular system to the cells and tissues where gas exchage is now termed internal respiration.

THE UPPER AIRWAYS OF THE RESPIRATORY TRACT

The upper airway function include:

*Heating or cooling inspired gases to body temperature ( 37 degrees Celsius )
* Filtering ( inhaled ) particles from the inspired gases
* Humidifying inspired gases to a relative humidity of 100 %
* Providing for the sense of smell, or olfaction
* Providing sounds, or phonation
*Ventilating, or conducting the gas down to the lower airways




The upper airways, starts at the nose, which are responsible for initially conditioning the inhaled air. The nose is a rigid structure made of cartilage and bone. There are 3 main regions contained within the space behind the nose, called the nasal cavity. The two nasal cavities are separated by a wall called the septal cartilage. The first region is the vestibular region, which is located inside the nostrils and contains the coarse nasal hairs that act as the first line of defense for the respiratory system. The hairs, called vibrissae, are covered with sebum,a greasy substance secreted by the sebaceous glands of the nose. It helps to trap large particles and keeps the nose hairs soft and pliable. The vestibular helps filter out large particles so they do not enter the lungs. The next is olfactory region, it is on the roof of the nasal cavity. And it keeps inspired gases into the region and does not allow it to go reach deeper into the lungs. The last is respiratory region, it warms and moistens air so airways do not dry out. The respiratory region possesses three scroll- like bones known as turbinates, or conchae. These split up the gas into 3 channels.




The second part is the pharynx, a hollow, muscular structure lined with epithelial tissues. It is also called throat, begins behind the nasal cavities and is divided into three sections: nasopharynx, oropharynx and laryngopharynx.

The nasopharynx is the uppermost section and begins right behind the nasal cavities. Air brethe through the nose passes through here. This section contains lymphatic tissue. The oropharynx is located right behind the oral or buccal cavity. Anything swallowed passes through this section. This section contains palatine tonsils. The laryngopharynx is the lowermost section. Its common name is voice-box. The larynx is a semi-rigid structure composed of cartilage. The " Adam's apple" is the largest cartilage. Air that is breathed and anything that is swallowed passes through this section. Glottis mechanism, directs the flow of " traffic "( air to the lungs and food and liquid to the stomach ). The glottis is the opening that leads into the larynx and eventually the lungs. The leaf-shaped, fibrocartilage, flap like structure that closes over the opening of the larynx when you swallow and opens up when you breathe is called epiglottis.

THE LOWER RESPIRATORY TRACT

Upon leaving the vocal cords in the larynx, the inspired air enters the trachea. The trachea extends from the cricoid cartilage of the larynx to the sixth cervical vertebrae. The cartilage found in the trachea is in the C-shaped structures. The trachea is the largest bronchus. Once the trachea reaches the center of the chest, it begins its first branching, or bifurcates, in two bronchi, the right and left main stem and can be called as generation 1. The site of bifurcation is called carina. Now the bronchi must branch into the five lobar bronchi ( generation 2 ) that correspond to the five lobes of the lungs. Each lung lobe is further divided into specific segments, ad the next branching of bronchi are called the segmental bronchi ( generation 3 ). The branching becomes more numerous with tiny sub-segmental bronchi ( generation 4 to 9 ) branching deep within each lung segment. The diameter of sub segmental bronchi ranges from 1 to 6 mm. Cartilaginous rings are now irregular pieces of cartilage and will soon fade away completely. Now we reach the very tiny airways called bronchioles ( generation 10 to 15 ) that average only 1 mm in diameter. They have no cartilage layer, and the epithelial lining becomes ciliated cuboidal. The cilia, goblet cells and submucosal gland, are almost all gone by generation 15. Now we reach the terminal bronchioles ( generation 16 ), which have an average diameter of .5 mm, no goblet cells, no cartilage, no cilia, and no submucosal glands. This marks the end of the conducting areas.

The next airways beyond the terminal bronchiole is called respiratory bronchiole ( generation 17 to 19 ) because a small portion of gas exchange takes place here. Alveolar ducts ( generation 20 to 22 ) originate from the respiratory bronchioles wherein the walls of the alveolar ducts are completely made up of simple squamous cells arranged in a tubular configuration. The alveolar ducts give way to the grape bunch-like structures of several connected alveoli, better known as the alveolar sacs ( generation 23 ).

..Carciovascular sysystem

I have learned in this system that the cardiovascular system has three major components include the heart (which is the organ that pumps blood through the system), blood ( a form of connective tissue that has a fluid component called 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). I have learned that blood vessels can be classified into arteries ( vessels that carry blood AWAY from the heart - which means that the blood carried by the arteries is deoxygenated), the arterioles ( smaller artery ), veins (vessels that carry blood TOWARDS the heart - which means that the blood carried by the veins is oxygenated), venules ( tiniest vessel) and capillaries (where the exchange of nutrients, gases and waste products happened - it was the transition vessels where blood begins its trip back to the heart). Blood is the transport of oxygen. It has two composition - plasma (the yellowish, straw colored liquid ) and formed solid ( include the Red blood cells (RBC) also called as erythrocytes, White blood cells (WBC) also called as leukocytes and Platelets also called as thrombocytes). I have leraned the different parts of the heart and how the blood go tho the different parts of the body.



If I will explain this to someone, I will discuss the three major components of the cardiovascular which is the heart, blood and blood vessels. I will explain the blood and its composition. The blood vessels and the classification of it. I will expalin how the blood go to the different parts of the bosy. From the superior vena cava (blood from head and arms) and inferior vena cava (blood from truk and legs), the deoxygenated blood will pass through the right atrium and will pass through the tricuspid valve because it is a one-way valve. After passing the first valve, the blood is now going in the right ventricle contracts increasing the internal pressure. This pressure closes the tricuspid valve and forces open the pulmonary valve thus sending blood toward the lung via the pulmonary artey. This blood will bacome oxygenated because while the blood is in the lung, the exchange of gases where happen here and then it will return to the left side of the heart. Oxygenated blood returns from the lung via the pulmonary vien and fills the left atrium creating a pressure against the mitral valve. This pressure of returning blood forces the mitral valve open and begins filling the left ventricle. The left ventricle contracts increasing internal pressure. This pressure closes the mitral valve and forces open the aortic valve causing oxygenated blood to flow through the aorta to deliver oxygen throughout the body.


Our teacher in Biology made this lesson easier for us in giving us lot of activities for us to remember the parts and the cardiac cycle. He explains it well and good..

.,The Different System.,

I have learned the different special senses such as sight, sound, taste, and smell. Also the other senses, such as general senses which are scattered throughout various regions of our body - heat, cold, pain, nausea, etc. - the cutaneous senses - touch, heatt, cold, pain- and lastly the visceral senses - hunger, thirst, and the need to urinate and defecate. I've learned also the different parts of our eyes and ears and the function.

If I will explain this to someone, I will draw or show them a picture of the senses. For the eye, I will show the internal and external structure of it and explain the function . For the ear, I will do the same and I will identify the three divisions of the ear which are the external, inner and middle. Not only the sense of sight and hearing but also the other senses. Like taste, touch, smell and etc. And I will explain the different disorders for the eye and ear.

Well, Patrick was the reporter but I'm not there when he's reporting. So, NO COMMENT to his report cause I don't know how he reported it.

.,eNdOcRinE sYstEM.,

I have learned in this chapter that the endocrine system produces and releases hormones into the blood to direct the activities of other body organs. I've learned also the different hormones of the different organs and its function.

If I will explain this to someone, as what I've done before, I will summarize it first and make a concept map. I will show them a picture of our body and the different organs. I'll identify first all the organs and tell the hormones of each. And ofcourse, the functions on how they work or what they do to our body. I will tell all the things I know in this lesson with understandable explanations.

Mikee was or should be the reporter. Because of unexpected happenings, she didn't reported her report..NO MUCH COMMENT!!!!