Role of capillaries

exchange material between blood and interstitial fluid

Intercellular clefts

water-filled space at junctions between cells

Types of capillaries

continuous, fenestrated, sinusoidal

Continuous capillary

endothelial cells form uninterrupted tube, surrounded by membrane - most tissues

Fenestrated capillary

fenestrae (pores) penetrate endothelial lining, surrounded by membrane - endocrine glands, choroid plexus, GI tract, kidneys

Sinusoids

discontinuous capillaries, flat and irregular shape, no surrounding membrane - liver, bone marrow, spleen

Precapillary sphincter

at entrance of capillary, ring of smooth muscle - alters blood flow

Metarteriole

- connects arterioles to venules - contains smooth muscle cells - regulates flow w/ diameter

F = P/R

P = pressure difference (mmHg) F = Flow (mL/min) R = resistance to flow (mmHg/mL/min)

What determines resistance to blood flow

Viscosity, length of BV, diameter of BV

Functions of cardiovascular system

- deliver oxygen/nutrients, remove waste - chemical signaling w/ hormones - thermoregulation (body temp) - inflammatory

Component of the cardio system

blood, blood vessels, heart

Arteries vs. veins

Arteries: blood away from heart vein: blood towards heart

Interatrial septum

separates left/right atria

Interventricular septum

separates left/right ventricles

Pulmonary circulation

- blood to and from gas exchanges surfaces of the lungs - blood entering lungs = deoxygenated - oxygen diffuses from lung tissue to blood - blood leaving lungs = oxygenated

Systemic circulation

- blood to and from rest of body - blood entering tissues = oxygenated blood - oxygen diffuses from blood to tissues - blood leaving tissues = poorly oxygenated

Series flow

blood must pass through pulmonary and systemic circuits

Pericardium and its functions

fibrous sac around heart - stabilizes heart in thoracic activity - protection - secrete pericardial fluid to reduce friction - limit overfilled chambers

3 layers of the pericardium

fibrous, parietal, visceral

Pericarditis

inflamed pericardium

cardiac tamponade

compression of heart due to accumulated pericardial fluid (decreases ventricular filling)

T/F: the right ventricular wall is thicker than the left

false

Components of the heart wall

Epicardium, myocardium, endocardium

2 types of cardiac muscle cells

myocyte: "Y", striated, one nucleus, many mitochondria intercalated disk: where desmosomes and gap junctions lie

Why are the heart muscles arranged spirally

when muscle contracts/shortens, wringing effect is produced and pushes blood upwards towards exit if arteries

4 valves of the heart

pulmonary, aortic (semilunar), left AV (mitral), right AV (tricuspid)

T/F: blood flow is bidirectional through the heart

False

T/F: energy is not used to open and close the valves of the heart

True, they work due to pressure gradients

AV valves

- prevent backflow of blood into atria when ventricles contract made of: cusps, chordae tendinea, papillary muscles

Chordae tendinea

extend from leaflet to papillary muscle

Papillary muscle

- cone shaped