Transport etc. Flashcards
Smooth muscle tissue
- Involuntary
- hollow visceral organs - liver, pancreas, aorta
Veins
- transport blood towards the heart against gravity (deox except pulmonary veins) - skeletal muscles, thin walls
- prevent backflow - valves
- low pressure - wide lumen
Cardiac cycle
- AV valves opened, blood flows into the ventricles, semilunar closed
- Atria contract - ventricles fill up
- Ventricles contract - AV close, 1st sound
- Semi-lunar open, blood moves into the Aorta (L, thinner walls, ox) and pulmonary artery (R, deox blood towards the lungs)
- Diastole - ventricles relax, semi-lunar close
Heart - structure
Superior Vena Cava - supplies oxygen-poor blood to the right ventricle
Pulmonary veins - supplies oxygenated blood to the left ventricle
Sinoatrial node - R atrium + Vena cava, generates electrical impulses, myogenic - SA node generates impulses, not external nerve impulses
Atrioventicular node - R, conducts electrical impulses, causes a delay between atria and ventricular contraction, ventricles fill up with blood fully
Tricuspid valve - R, unidirectional blood flow
Mitral valve - L
Septum
Transpiration
Evaporation of water in the leaves, mesophyll cells —> stomata, into the atmosphere
- nutrient transport
- hydrostatic pressure, pressure within a cell
- water cycle
Tension
Neg pressure - water loss from transpiration, creates a driving force, pulls water upward
Dicotyledonous plant structure - ring organisation of vascular bundles
Epidermis - barrier, prevents water loss
Cortex - surrounds vascular bundles
Vascular bundles:
- Xylem - thick lignin walls, no end cell wall, transport of water and minerals, upward flow,
- Pits - unlignified areas in the Xylem wall
- Cambium - production of Xylem and Phloem
- Phloem - perforated end walls (sieve plates), closer to epidermis, transport sugar (sucrose) and amino/mRNA/hormones, bidirectional
Pith - center, storage
Translocation
Phloem, transport from sources (leaves, photosynthesis) to sink (roots, fruits meristematic tissues) cells, hydrostatic pressure —> sucrose actively transported into the phloem, drives in water by osmosis
Capillaries
Single cell thick endothelium - efficient exchange of materials between blood and tissues
Low blood pressure
Fenestrated
Artery
Away from the heart (oxygenated except pulmonary), thick, smooth muscle walls, tunica intima - corrugated (when contracted) endothelium allows stretching / tunica media - thick smooth muscle w elastin fibres, high pressure / tunica externa - connective tissue w collagen fibres, stretch and recoil
Vasoconstriction
Narrowing of the arteries/arterioles, maintaining core body temp, flow rate
Diastolic pressure
Presssure in the arteries when the heart is relaxed, mmHg
Release and reuptake of tissue fluid in the capillaries
Tissue fluid - oxygen, glucose, blood plasma substances
Release - near arteriole supplying blood at high pressure, tissue fluid without large protein molecules flows between the cells
Oxygen - passive diffusion / Glucose - Sodium-glucose cotransporters / Amino acids - active transport into growing cells
Reuptake - near venules (connection to vein), low blood pressure, CO2 from cell respiration excreted and reabsorbed, some tissue fluid passes into the lymph vessels, lymph is drained from the body and returns to the heart by the vena cava
Why do fish have a single circulation?
They pump blood to their gills to be oxygenated, it can be at high pressure since the water pressure will slow it down, preventing the capillaries in the narrow gill filaments from bursting
Cardiac muscles
- Branched cells with connected plasma membranes to adjacent cells - allows the conduction of electrical impulses (SA - myogenic, sends impulse for cells to depolarize), many mitochondria, sarcoplasmic reticulum that stores Ca2+
Ventricular pressure
LEFT - largest curve, 1st sound AV valves open , 2nd AV valves close
Aortic pressure
Decreasing curves, 1st sound Semilunar valves open before increase, Semilunar valves close - little V
VAAt
(L) Ventricular > Aortic > Atrial pressure graphs
Muscle contraction
- Myosin head (thick f) attaches to actin myofilament (cross-bridge) - high energy configuration
- Inorganic P from previous cycle initiates power stroke, Myosin head pulls the a filament towards the M-line (center of the sarcomere), ADP released
- ATP attaches to the myosin head breaking the cross-bridge - low energy configuration
- ATP hydrolysis (ADP+Pi), myosin head is energised
Necessary for muscle contraction
High Ca2+ concentration, ATP available
