B3.2- transport Flashcards
(33 cards)
arterioles and venules
arterioles=smallest arteries and venules=smallest veins
-form capillary bed
adaptation of capillaries
- large surface area for exchange processes
- lumen can only fit single file cells
- thin walls, one cell thick made of endothelium cells 4. large pores (fenestrations) in capillary walls allows large volume of tissue fluid to be produced.
Artery structure
(carries blood away from heart at high pressure)
1. thicker walls
2. narrow lumen
3. elastic fibers and collagen in walls
4. smooth muscle
vein structure
(return blood to heart- not high pressure)
1. thin walls
2. wide lumen
3. contains valves
coronary arteries
=arteries that supply blood to cardiac muscle
atherosclerosis
the hardening and narrowing of arteries due to build up of plaque (cholesterol/triglycerides) in artery walls
occlusion of coronary arteries
=substances build up in lumen of arteries and restricts blood flow
-macrophages attracted to site of artery damage and releases growth factors which stimulates development
-if occluded artery is coronary= a heart attack. Heart deprived of o2
risk factors of coronary heart disease
- high blood pressure
- smoking
- obesity
- inactive lifestyle
- high cholesterol
- age/diet/genetics
transpiration
movement of water through plant and its evaporation from leaves
translocation
movement of nutrients/sap
transport of water from roots to leaves
-water enters root by osmosis
-water travels to leaves through xylem vessel
-water is drawn out of xylem moving through cell walls by capillary action to replace water lost by mesophyll cells
-water loss in xylem causes negative pressure in the leaves
adaptation of xylem vessel
xylem vessel=hollow tubes of dead, stacked cells.
1. lack of cell walls- end of walls between cells are removed. Cell components break down creating long, continuous tubes
2. pits for entry and exit of water and allows water to move between adjacent xylem
3. side walls are thick and fortified with lignin to prevent collapsing
features of cross section of dicotyledonous root and stem
- epidermis= protection and prevents water loss
- cortex= support and stores starch
- vascular bundles= contain xylem and phloem, transports minerals
- xylem= water and minerals up stem
- phloem- organic compounds up and down stem
tissue fluid
liquid formed by leaking of blood plasma into surrounding cells, enabling exchange of materials between blood and cells
process of tissue fluid release and uptake
-high pressure and volume in capillaries cause some plasma to filter out through capillary walls
-fluid makes tissue fluid, in which large substances cant pass through (red blood cells and large proteins)
-plasma fluid provides o2 and nutrients for cells
-co2 moves out of all cells into tissue
-when near venules, due to lower pressure and high concentration of plasma proteins, tissue fluid filters back into the capillaries. The remaining taken by lymph capillaries
blood components not present in tissue fluid
-red blood cells
-large plasma proteins
drainage of excess tissue fluid into lymph ducts
-is taken up by lymph ducts (lymphatic capillaries)
-the fluid now becomes lymph
-lymph vessels join to make wider lymphatic vessels
-fluid vessels to make up wider lymphatic vessels
-fluid returns to blood via lymph nodes
adaptations for lymph vessels
1) gaps= allow tissue fluid to enter
2) thin walls= moves tissue fluid
3) valves= prevent backflow via lymph fluid
sing circulatory system in bony fish
-heart has one ventricle
-pumps deoxygenated blood to gills
-after passing through gills, becomes oxygenated and flows directly to organs
-deoxygenated blood returns to heart
double circulatory system in mammals
-heart has 4 chambers
-right side pumps blood to lungs
-blood becomes oxygenated as it passes through capillaries in lungs
-oxygenated blood returns to left side of heart and pumped to body
-gas exchange in body tissue
-deoxygenated blood returns to right side of heart
cycle of heart
-deoxygenated blood into vena cava
-enters right atrium (volume increase)
-sinoatrial node makes atria contract
-atrial ventricular valve opens
-right atria enters ventricle
-ventricle increases in volume
-atrial ventricular valve closes
-semi lunar valve opens due to high pressure
-blood pushed out of pulmonary artery
adaptations of heart
- atria = collecting chambers
- ventricles= pumping chambers, thick muscular wall, thicker on left
- septum= wall between 2 sides makes sure heart is a double pump, oxygenated/deoxygenated blood does not mix
- atrioventricular valves= between atria and ventricle
- semi lunar valve= between ventricles and arteries- prevents backflow
- cardiac muscle= allows heart contraction at high pressure, stimulated by a nerve (myogenic contraction)
- Coronary vessels= muscular wall has own supply of oxygen
- sinoatrial nerve (pacemaker) region of specialised cardia muscle in right atrium wall which initiates contraction;
Control of cardiac cycle by SA node
Sa node controls heart beat in right atrium wall. Sends an electrical impulse which spreads out resulting in atria undergoing systole
-SA node reaches AV node located at the bottom right atrium in septum
-AV node receives impulse and slightly delays its own action potential that travels down Purkinjie fibers
-Action potential travels up walls of ventricles initiating ventricular systole.
Systole and diastole
systole= the contraction of heart muscles
diastole= the relaxation of heart muscles
