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Study Notes

Circulation (Heart)

Blood Vessals

Blood Vessel	Structure	Thickness of Wall	Valves	Direction of Blood Flow
Arteries	3 layers, endothermus, elastic fibers, smooth muscle.	2.5 mm wide	No	Away from heart.
Arterioles	Elastic tissue, smooth muscle fibre.	Under 0.5mm to naked eye.	No	Away from heart.
Capillaries	One cell thick walls, one endotherum membrane.	8-10mm wide	No	To heart and away.
Venules	Same 3 layers as arteries, less smooth muscle.	Thin walls	Yes	To heart.
Veins	Same 3 layers as arteries, less smooth muscle.	Thin walls	Yes	To heart.

Identify and give functions for each of the following :

Subclabian arteries and veins : blood vessels located in the chest region of the body, which serve to transport blood to the head and arms to and from the heart

Jugular veins : branch off the subclacian vein which brings deoxygenated blood from head and arms back to heart

Carotid veins : blood vessels along neck

Mesenteric Veins : arteries which branch off the aorta it serves blood to the digestive tract

Anterior and posterior vena cava: superior and inferior venacava which bring blood to the right atrium

Pulmonary veins and arteries: veins and arteries which bring blood to the lungs and exchange substances at the lungs capillary beds.

Hepatic portal vein: veins that connect small intestine with the liver

Renal arteries and veins : blood vessels which bring and take away blood at the kidneys

Iliac arteries and veins : blood vessels which transport blood between the legs and heart

Coronary arteries and veins : the external coronary arteries are the first branch off the aorta, They eventually become arterioles caloillaries and veins.

Aorta : major systemic artery that receives blood from left ventricle

Distinguish between pulmonary and systemic circulation:

Pulmonary circulation is the circulation of blood between the heart and the lungs. Systemic circulation is the circulation of blood between the heart and the rest of the body parts that require oxygen to function.

Identify and describe differenced in structure and circulation between fetal and adult systems :

The featus has several structures in its circulatory system that the adult does not.

1.) Foramen ovale-an opening between the two atria. This opening is covered by a flap of tissue that acts as a valve, It travels between the atria so less blood enters lungs.

2.) Arterial Duct- is a connection between the pulmonary artery and aorta. It functions as to keep deoxygenated blood from being circulated back into fetus developing brain.

3) Umbilical artery-carries deoxygenated blood and wastes to the placenta.

4) Umbilical Vein- carries oxygenated blood and nutrients to the baby from the placenta

5) Venous duct-is connected between the umbilical vein and inferior vena cava.

Demonstrate a knowledge of the path of blood from the aorta through the body and back to the left ventricle:

List major components of plasma :

-water (maintains blood volume and transports molecules)

-plasma protein

-Albumin (transports bilirubin, maintains blood volume and pressure)

-Fibrinogen (clots)

-Immunoglobulins (transport, fight infection)

Describe the shape, function and origin of the red blood cells, white blood cells and platelets:

-Red blood cells are bright red to dark purple binoconvave disks without nuclei. Theay are made in the red bone marrow of the skull. They originate as erythrocyte stem cells in the red bone marrow. They function to transport O2 and CO2. The red pigment hemoglobin protein allows the cell to acquire oxygen in lungs, and give it up in the tissues.

- White blood cells are larger, have a nucleus. And appear translucent. They are divided into granular and agranular leukocytes. They are formed in red bone marrow. They function to fight infection.

-Platelets are fragments of megokaryocytes in red bone marrown. They function as to aide blood clot or coagulate.

Circulatory System- Heart Structure and Function

Identify and give functions for each of the following :

a) Left and right atria: upper chambers of the heart which receive blood

b) Left and right ventricles: lower chamber of the heart which sends blood to the major veins and arteries

c) Coronary arteries and veins : serve the heart muscle itself. The coronary arteries lie on the external surface of the heart where they become capillary beds, venules and cardiac veins, which empty into the right atrium.

d) Anterior and posterior vena cava: major vein connected to the right atrium, which carry deoxygenated blood

e) Aorta : major artery of the body, connected to the left ventricle, transports blood to the systemic circuit

f) Pulmonary artery and veins : part of the pulmonary circuit which transport blood from/to the heart and lungs

g) Pulmonary trunk : immediate artery after right ventricle. Branches into the left and right pulmonary veins. Functions as to transport deoxygenated bloods to the lungs in the capillaries.

h) Atrioventricular Valves: supported by strong fibrous strings called chordate tendiae, which support the valve and prevent them from inverting when the heart contracts. They direct the blood flow and prevent its backward movement between the atria and ventricles.

I) Chordae tendinae :strong fibrous strings that support the atrioventricular valve. It is attached to muscular projections of the ventricular walls.

j) Semi-lunar valves : direct the flow of blood and prevent its backward movement between the right ventricle and the pulmonary Turk, and the left ventricle and the aorta.

k) Septum : a wall inside the heart that separates the heart into a right and left side.

Describe the location and functions of the SA node, AV node and Purkinje fibers:

-          SA node is found in the upper dorsal wall of the right atrium. It initiates the heartbeat and automatically !

-          AV node is found in the base of the right atrium very near the septum.The AV node signals the ventricles to contract by way of large fibers terminating in the more numerous and small purkinje fibers.

-          -Purkinje fibers line the heart and cause the ventricles to contract.

Describe autonomic regulation of the heartbeat by the nervous system :

The autonomic system has two divisions : the parasympathetic system, and the sympathetic system. The parasympathetic system causes the heartbeat to slow down and sympathetic speed up. Factors such as the relative need for oxygen or blood pressure determine which of these systems is activated.

Relate factors that affect and regulate blood pressure to hypertension and hypotension :

Hypertension is systolic pressure , the lowest arterial pressure.

Hypotension is diastolic pressure, the lowest arterial pressure.