B3.2 Transport Flashcards
arteries, veins, capillaries, xylem, phloem, single vs double circulation, cardiac cycle
describe the pathway of blood from arteries to veins
blood flows through arteries, which branch into arterioles, then capillaries; capillaries join back together to form venules, then veins
structure of capillaries
1 cell thick lumen, outer, and inner layer
fenestrations
slits in capillaries allowing larger molecules through faster
adaptations of capillaries for chemical exchange
thin walls, small diameter, permeable, large surface area, fenestrations
artery structure
small lumen, inner elastic fibre layer, then thick smooth muscle, then collagen
vein structure
large lumen, inner elastic fibre layer, then thin smooth muscle, then collagen
adaptations of arteries for pumping high-pressure blood
- smooth muscle changes diameter to regulate blood pressure, controlled by automatic nervous system
- elastic walls stretch on blood surge, recoil and increase pressure to propel blood afterwards
adaptations of veins for moving low-pressure blood
undirectional, slow flow of blood helped by internal valves preventing backflow and compression from muscles
what vessels supply blood to cardiac muscle?
coronary arteries
plaque
build-up of cholesterol and other substances in arteries, causing occlusion
coronary heart disease
when plaque builds up in coronary arteries, causing heart attack
artherosclerosis
hardening and narrowing of arteries due to plaque, caused by macrophages attaching to damage sites, stimulating tissue growth and consuming cholesterol
epidemiological
relating to the incidence, distribution, and control of diseases such as coronary heart disease
Pearson correlation coefficient
quantifies correlations; if close to 0, no relationship
cohesion-tension theory
water transpires, pulling water up xylem by capillary action, creating tension, which pulls water up as one unit as a result of cohesion
xylem structure
dead, hollow cells connected to form tube, no cell walls between, pits in sides to let water in/out, fortified with lignin, which resists collapse from tension
two categories of flowering plants
monocotyledon, dicotyledon
draw and label cross-section of dicotyledonous stem
out to in: thin epidermis, cortex, inner layer with vascular bundles with phloem and xylem in them, lumen; circular
draw and label cross-section of dicotyledonous root
out to in: thin epidermis, cortex, vascular bundle with phloem and xylem; squiggly
pressure filtration
increased hydrostatic pressure in arteriole end of capillary bed results in walls opening and plasma leaving to become tissue fluid; fluid returns to capillaries again at venule end because of oncotic pressure
describe the flow of lymph in lymphatic capillaries
- some tissue fluid enters lymphatic capillaries rather than capillary bed, becoming lymph
- internal valves and muscle contractions help lymph to travel from lymphatic capillaries to ducts to trunk then released back to vein
- lymph nodes along trunk filter bacteria, cancer, etc. in lymph before re-entering blood
pulmonary vs systemic circulation
blood flow to and from lungs vs body tissues
describe direction of blood flow in single circulation in fish
- deoxygenated blood pumped from two-chamber heart to capillary beds in gills (pulmonary circulation)
- blood becomes oxygenated and travels to capillary beds in body tissues (systemic circulation)
- deoxygenated blood travels back to heart
describe direction of blood flow in double circulation in mammals
- deoxygenated blood enters interior/superior vena cava and into right atrium of four-chamber heart
- travels through tricupsid/right atrioventricular valve and into right ventricle (pulmonary circulation)
- travels through right semilunar valve and pulmonary artery to capillaries in lungs
- oxygenated blood travels through pulmonary veins and into left atrium
- travels through bicupsid/left atrioventricular valve and into left ventricle (systemic circulation)
- travels through left semilunar valve and into aorta to be pumped to body tissues
