Friday, October 25, 2013

Gas Exchange During Respiration


1.) The direction of gas movement is determined by:
DD. Partial pressure differences.

2.) Which of the following statements about partial pressures of gases is true?
BB. PO2 in the lung is greater than PCO2 in the blood; PC02 in the lungs is less than PC02 in the blood.

3.) Which of the following statements about partial pressures of gasses is true?
BB. PO2 in blood is greater than PO2 in tissues; PCO2 in blood is less than PCO2 in tissues

4.)Oxygen-rich blood is carried through pulmonary arteries from the lungs to the heart
False

5.)Oxygen-poor blood is carried through systemic veins from the body tissues back to the heart.
A.True.

Friday, October 18, 2013

The relationship of the lymphatic vessels to the blood vessels

The lymph begins as a tissue fluid derived from blood capillaries, then enters the lymph capillaries and then travels through the lymphatic vessels and nodes. It then enters the blood steam through veins at the root of the neck. 



Blood vessels carry nutrients, water, oxygen and waste products to and from your body cells. There are three primary types of blood vessels: arteries, capillaries, and veins. The functions include transporting blood away from the heart (arteries), transporting blood toward the heart (veins), and capillaries, which connect the arteries to the veins.

The lymphatic vessels pick up and return excess tissue fluid to the blood vascular system.
The vessels carry lymph from peripheral tissues to the venous system. The lymphatic system transports lymphocytes, is involved in the removal of foreign matter & cell debris by phagocytes & is part of the body's immune system. It also transports fats from the small intestine to the blood.


Components of the lymphatic system:

Lymphatic vessels, Lymph nodes, Spleen, Thymus, Tonsils, Peyer’s Patches, Appendix










Work cited: http://www.lymphedemablog.com/wp-content/uploads/2011/09/Lymphatics.gif

Saturday, October 12, 2013

Endorine Gland Stimuli: Hormonal, Humoral and Neural



     Various endocrine glands are stimulated to manufacture and release their hormones by three main types of stimuli -Hormonal, Humoral and Neural. 

Hormonal is the most common it releases hormones in response to hormones produced by other endocrine organs. For example: the hypothalamic secrete hormones that stimulate the anterior pituitary, which stimulate glands to secret hormones (thyroid gland, adrenal cortex and gonads).

Humoral secret hormones in direct response to changing blood levels of ions and nutrients. Declining blood Ca2+ concentration stimulates the parathyroid glands to secrete PTH (parathyroid hormone) PTH causes Ca2+ concentrations to rise and the stimulus is removed. Other hormones releases due to humoral are calcitonin and insulin. 

Neural, in some cases, nerve fibers stimulate hormone release. For example, catecholamine (epinephrine and norepinephrine) is released during times of stress by stimulation of the adrenal medulla by the sympathetic nervous system. Also, the hypothalamus stimulates the release of oxytocin and anti-diuretic hormone by neural stimulation.


Wednesday, October 2, 2013

Five formed elements and their functions


Five formed elements and their functions

1.     Erythrocytes or red blood cells (RBSs)- The primary function of these cells is to carry oxygen and carbon dioxide to all parts of the body. They deliver oxygen to the tissues and return carbon dioxide rom the tissues to the lungs. They are the most numerous in the blood.  Erythrocytes do not need a nucleus to carry out the function of the transport of oxygen and carbon dioxide.

2.     Leukocytes or white blood cells (WBCs)-White blood cells provide protection against foreign organisms and matter. They circulate throughout the body and tissues. To carry out their function the white blood cell must be highly mobile. They are confined to the blood stream and slip in and out of blood vessels.


3.     Platelets also know, as megakaryocytes-Their main function is to form clots to stop bleeding. It also plays a huge role in homeostasis (prevention of blood loss).


4.     Granulocytes: Neutrophils- is phagocytes that are partial to bacteria and fungi, which they destroy when they invade.


      5.   Eosinophils- they increase during infections of parasites.  They gather and release enzymes from their cytoplasmic granules onto the parasite and digest   it away.