exam review 2

What are the three layers of blood vessels?

Tunica externa (adventitia), Tunica media, Tunica intima.

What is the function of the tunica externa?

It is the outer protective layer made of epithelial cells, connective tissue, and elastic fibers.

What is the largest layer of a blood vessel?

Tunica media, containing elastic fibers and smooth muscle that controls vessel diameter.

What characterizes arteries?

They carry blood away from the heart and operate under high pressure.

What are elastic arteries?

The largest arteries, containing more elastic fibers (e.g., aorta).

What distinguishes muscular arteries?

They contain more smooth muscle and distribute blood to organs.

What are arterioles?

The smallest arteries that control blood flow and blood pressure.

What are precapillary sphincters?

Muscles that control blood flow into capillaries based on oxygen needs.

What is an aneurysm?

A weak, bulging area in a vessel wall.

What defines capillaries?

They are one cell thick and are the site for the exchange of nutrients, gases, and waste.

What are continuous capillaries?

Capillaries with tight junctions that allow small molecule exchange.

What are fenestrated capillaries?

Capillaries that contain pores to allow for filtration, such as in the kidneys.

What are sinusoidal capillaries?

Capillaries with large gaps that allow proteins and cells to pass, found in the liver.

What is the function of veins?

They carry blood toward the heart under low pressure and often contain valves.

What are venules?

The smallest veins that connect to capillaries.

What characterizes medium veins?

They are veins of intermediate size.

What defines large veins?

The largest veins, such as the inferior vena cava.

What is venous return?

The mechanism by which blood returns to the heart, assisted by valves, skeletal muscle pump, respiratory pump, and cardiac suction.

What is a blood reservoir?

Veins that hold most of the blood in the body.

What is the blood flow pathway from the heart?

Heart → artery → arteriole → capillary → venule → vein → heart.

What is a portal system?

A system where blood flows through two capillary beds before returning to the heart.

What are anastomoses?

Connections between vessels providing alternate pathways.

What is perfusion?

Blood flow to a tissue.

What is blood pressure (BP)?

The force of blood against vessel walls.

What is systolic pressure?

The pressure during heart contraction.

What is diastolic pressure?

The pressure during heart relaxation.

What is pulse pressure?

The difference between systolic and diastolic pressures.

What is MAP (mean arterial pressure)?

A measure calculated as (Systolic - Diastolic)/3 + Diastolic.

What are Korotkoff sounds?

Sounds heard while measuring blood pressure with a cuff.

What is arteriosclerosis?

The stiffening of vessel walls.

What is atherosclerosis?

The buildup of plaque in blood vessels.

What factors depend on blood pressure?

Cardiac output, blood volume, and resistance.

What is cardiac output?

The amount of blood pumped by the heart per minute.

What is vascular resistance?

The opposition to blood flow in the vessels.

What happens when vessel diameter decreases?

Resistance increases, leading to increased blood pressure.

What effect does increased vessel length have?

It increases resistance.

What does increased viscosity do to blood flow?

It increases resistance.

What is local control in blood flow?

Adjusting blood flow based on tissue needs, such as dilation in response to low oxygen.

What is neural control of blood flow?

Control mechanisms involving baroreceptors, chemoreceptors, and medullary reflexes.

What do baroreceptors detect?

Changes in blood pressure.

What do chemoreceptors monitor?

Oxygen, carbon dioxide, and pH levels.

What is hormonal control of blood pressure?

The regulation involving hormones like angiotensin II, aldosterone, ADH, and natriuretic peptides.

What does angiotensin II do?

Causes vasoconstriction and increases blood pressure.

What is the function of aldosterone?

Retains sodium and water, leading to increased blood pressure.

What is ADH (vasopressin)?

A hormone that retains water, increasing blood pressure.

What do natriuretic peptides do?

They decrease blood volume and blood pressure.

What are catecholamines?

Hormones like epinephrine and norepinephrine that increase blood pressure.

What is diffusion?

The movement of small molecules (e.g., O2, CO2, glucose) across membranes.

What is transcytosis?

The movement of large molecules via vesicles, such as insulin.

What is bulk flow?

The movement of fluid due to pressure differences.

What is blood hydrostatic pressure (BHP)?

The pressure that pushes fluid out of capillaries.

What is blood colloid osmotic pressure (BCOP)?

The pressure that pulls fluid into capillaries, primarily due to albumin.

What is interstitial fluid osmotic pressure (IFOP)?

The pressure that pulls fluid out of capillaries.

What is interstitial hydrostatic pressure (IFHP)?

The pressure that pushes fluid into capillaries.

What is net filtration pressure (NFP)?

Calculated as (BHP + IFOP) - (BCOP + IFHP).

What does a positive NFP indicate?

Filtration, meaning fluid leaves the blood.

What does a negative NFP indicate?

Reabsorption, meaning fluid enters the blood.

What is filtration?

The movement of fluid from blood to tissues.

What is reabsorption?

The movement of fluid from tissues back to blood.

What is osmosis?

The process where water follows solutes, particularly albumin.

What is facilitated diffusion?

Transport of molecules using membrane proteins.

What is edema?

The accumulation of excess fluid in tissues.

What are the causes of edema?

Increased hydrostatic pressure, decreased albumin, and lymph blockage.

What does the pulmonary artery do?

Carries deoxygenated blood to the lungs.

What does the pulmonary vein do?

Carries oxygenated blood to the heart.

What is the function of the umbilical vein?

Carries oxygenated blood to the fetus.

What does the hepatic portal vein carry?

Blood from the GI tract to the liver.

What does the celiac trunk supply?

Abdominal organs.

What do the internal and external jugular veins do?

Drain blood from the brain and superficial head, respectively.

What is the lymphatic system?

A network that returns fluid, provides immunity, and absorbs fats.

What is lymph?

A clear fluid similar to plasma but with lower protein content.

What do lymphatic vessels do?

Carry lymph, contain valves, and ensure one-way flow.

What is the lymph flow pathway?

Capillaries → vessels → nodes → trunks → ducts → veins.

What does the right lymphatic duct drain?

Drains lymph from the right upper body.

What does the thoracic duct drain?

Drains lymph from the rest of the body.

What is lymphatic tissue?

Lymphocytes and macrophages found in tissues.

What is MALT?

Mucosa-associated lymphoid tissue in mucous membranes.

What are Peyer’s patches?

Lymphatic tissues located in the small intestine.

What are primary lymphatic organs?

Bone marrow and thymus.

What are secondary lymphatic organs?

Lymph nodes, tonsils, and spleen.

What is the role of bone marrow?

It produces blood cells.

What is the function of the thymus?

It matures T cells.

What do tonsils do?

Trap pathogens entering the body.

What is the role of lymph nodes?

They filter lymph and activate the immune response.

What does the spleen's red pulp do?

Removes old red blood cells.

What does the spleen's white pulp do?

Involves immune response by activating B and T cells.