B3.2 Transport Flashcards
(83 cards)
1
Q
What are 2 examples of organs where there are dense capillary networks?
A
The Lungs and small intestine.
2
Q
What is the average width of a capillary?
A
10 micrometres
3
Q
Why do capillaries have a large total surface area?
A
They branch and rejoin repeatedly to form a network with a huge total length.
4
Q
How to blood cells pass through capillaries?
A
Blood cells pass through in a single file?
5
Q
What supports the one layer of endothelium cells in blood capillaries?
A
A coating of extracellular fibrous proteins.
5
Q
What is a protective role of the basement membrane?
A
It filters macromolecules such as proteins, allowing only small or medium-sized particles to pass through.
6
Q
A
7
Q
What features allows fluid to pass through the blood capillaries?
A
- The blood pressure inside is higher than the surrounding tissues.
- Pores between the epithelium allow the fluid to pass through.
8
Q
How do the capillaries supply oxygen and other useful substances to the cells in the surrounding tissues?
A
By releasing tissue fluid containing oxegyn, glucose, and other useful substances to flow between cells and allow them to absorb useful substances and excrete waste products.
9
Q
What is the function of Arteries?
A
They carry pulses of high-pressure oxegyn aged blood from the heart to every organ of the body.
10
Q
What is the function of veins?
A
They carry a stream of low pressure deoxygenated blood from the organs back to the heart.
11
Q
What are the structural adaptations of arteries?
A
- Thicker walls
- Narrow Lumen
- Corrugated inner surface
- Fibers in the walls
12
Q
What are the visible structural adaptations of veins?
A
- Thinner walls
- Wider Lumen
- Circular/Flattened
- Smooth inner surface
- No/few fibers visible in walls
13
Q
What are the general layers of arteries and veins?
A
- Tunica Externa
- Tunica Media
- Tunica Intima
- Lumen
14
Q
What are the adaptations (form and func) of the artery tunica externa?
A
- Its connective tissues contain tough collagen fibers that prevent swelling, bursting, or aneurysms during high blood pressures.
15
Q
What are the adaptations (form and func) of the artery tunica externa?
A
- Its connective tissues contain tough collagen fibers that prevent swelling, bursting, or aneurysms during high blood pressures.
16
Q
What are some adaptations of the artery tunica media?
A
- Thick layer for strength
-Contains smooth muscle and elastic fibers to help pump blood by transmitting the pulse.
17
Q
What are some adaptations of the artery tunica intima?
A
- It’s lined by smooth endothelium that reduces resistance to flow.
- In some arteries there is a layer of elastic fibers.
18
Q
What are some adaptations of the arterial lumen?
A
- It’s a narrow space so it helps maintain high blood pressure and velocity of blood flow.
19
Q
Collagen Fibres
A
Rope-like proteins with high tensile strengths
20
Q
State the structural changes that occur within arteries with systole and diastole:
A
- (systole - ventricles pump, high pressure blood enters) Wall of artery expands due to the high pressure and elastic fibers in the wall stretch and store potential energy.
- (Diastole -ventricles stop pumping, blood pressure declines) elastic fibers recoil, applying pressure on the lumen which helps pump blood on along the artery and makes flow more even.
21
Q
How are smooth walls in artery walls adapted to their function?
A
- circular, make the lumen narrower during vasoconstriction and wider during vasodilation.
- high density of smooth muscle fibers in arterioles, blood flow in each organ can be adjusted.
22
Q
Systole
A
When ventricles pump blood, a time of high pressure.
23
Q
Diastole
A
When ventricles stop pumping blood, a time of lower blood pressure.
24
How can you measure pulse rate?
- Place your index and middle finger on your carotid or radial artery until the pulse is reliably felt.
- User a timer to count beats per minute.
25
How does a pulse oximeter work?
It has LEDS that shine light into the finger and detectors to measure how much light is absorbed by the finger, which depends on the amount of blood in the tissues.
26
What are some adaptations in the layers of veins?
- Tough outer coat of connective tissue in the externa to prevent leak.
- Few elastic fibres in the thin media as blood pressure is low.
- Smooth endothelium in intima to resistance to flow.
- Wide lumen to accommodate slow-flowing blood.
27
Describe the structure of valves in the veins:
- Tissue consisting of three pocket-flaps of tissue.
28
Why does deoxygenated have a risk of back flow towards the arteries?
- Very low blood pressure and no pulse.
29
How do valves prevent the risk of backflow to the capillaries in veins?
- If blood starts to flow backwards, it gets caught in the flaps, filling them and closing the valve. Blood flowing towards the heart will push the valve open.
30
How many coronary arteries are there?
3
31
Outline the function of the coronary arteries branching from the aorta:
Supply blood to the muscular wall of the heart.
32
Atheroma
Deposits of lipids (fats or cholesterol) in the walls of arteries.
33
How does atheroma restrict blood flow and potentially cause blockage (Occlusion)?
It makes the lumen of the artery narrower by building up.
34
What does the umbrella term “Coronary heart disease” refer to?
Medical conditions due to narrowed or blocked coronary arteries.
35
Angina
A pain in the chest caused by a restriction in the blood flow to the heart when coronary arteries are blocked/narrowed.
36
Epidemiology
Research into the nature and spread of diseases in the human population.
37
Risk factors for CHD include:
- Hypertension
- Smoking
- Obesity
- Family history
- Hypercholesterolemia
- Diabetes
38
Which vessels transport water in flowering plants?
Xylem vessels with low concentrations of K+ and other dissolved ions.
39
Transpiration in leaves
The evaporation of water from walls of spongy mesophyll cells and their diffusion out through stomata.
40
Form: Cells walla contain a mesh of cellulose molecules That are hydrophilic and can form hydrogen bonds.
Function?
Any water lost by evolution fromnteh surfaces of leaves is replaced by water drawn through pores between celluslose molecules in leaf cells due to cohesion between water molecules and adhesion of water to cellulose.
41
Transpiration pull
Tension generated in the leaf that is transmitted down xylem vessels due to cohesion between water molecules.
42
Why makes the transpiration pull important?
It can transport water passively against the force of gravity to the leaves of a tree.
43
Side walls of xylem vessels are thickened and infused with lignin polymers, how does this adapt them to their function?
It prevents the vessels from collapsing when pressure inside is very low as the the plant is transpiring.
44
How do xylem vessels keep the flow of water unimpeded and a passive process when mature?
The end walks between adjacent cells are removed during xylem vessel development and the plasma membrane and cell content breaks down, creating long, continuous tubes.
45
Xylem vessels have pits or gaps in their walls, how does this make them adapted for their function?
It allows water to exist and enter, especially since xylem walks are impermeable to H20.
46
Dicotyledons (Dicots)
Plants with two embryo leaves in their seeds.
47
Epidermis in Dicot stems
Single layer of cells with waxy cuticle on the outside to reduce water cells.
48
Pith
Large, thin-walled cells that fill the center of the stem.
49
Cortex in Dicot stems
Medium-sized thin-walled cells that strengthen the stem when turgid.
50
Xylem in Dicot stems
Wide tubuler structures with thick walls, round in cross section that transport water and mineral ions.
51
Epidermis function in dicot ROOTS
Absorbs water and minerals from the soil using root hairs.
52
Phloem function in dicot roots
Transports sugars and other food from the leaves to the roots.
53
Xylem function in dicot roots
Transports water and mineral ions to the stem and leaves.
54
Cortex function in dicot roots
Bulks out the root to strengthen it and increase the surface area.
55
How is tissue fluid formed? (Pressure filtration)
Capillary walls are permeable and blood is initially at high pressure, so some of the blood plasma leaks out forming tissue filled.
56
Venules
Vessels that unite to form veins (little veins).
57
Why does blood drain out of capillary networks into venules in terms of concentration gradient?
Low blood pressure in venules and higher in capillary networks.
58
Which gradient alteration allows tissue fluid that is nutrient depleted and deoxygenated to re-enter the capillaries?
Drainage from blood capillaries into venules lowers blood pressure in capillaries and allows the fluid to move with that gradient.
59
Outline the process of tissue fluid Oxegynation and deoxygenation:
- Tissue fluid with o2 and C6H12O6 exits blood capillaries.
- Cells absorb useful materials and excrete waste products.
- Tissue fluid with waste products re-enters capillaries that merge to form venules that merge to form veins that carry the blood to the lungs for oxegynation.
60
Which organ detoxifies the waste products from blood plasma?
The liver, but they are excreted by the kidney.
61
How many liters of the 20 liters of tissue fluid produced per day return to the capillaries?
17
62
Oedema
Swelling caused by the remaining 3 liters staying in the tissue.
63
What happens to the tissue fluid entering the lymphatic vessel drainage system?
- returned to the blood circulation via 2 large lymphatic ducts that merge with the left and right subclavian veins.
- Blood in subclavian veins flows into the vena cavas and on to the right side of the heart.
64
Describe the structure of lymphatic vessels?
- Narrow, blind-ended that join up to form wider lymphatic vessels with valves.
65
State the pathway of blood circulation in fish:
- Deoxygenated blood is pumped by the heart to the gills
- The gills oxegynate the blood
- Having enough pressure, the blood flows directly to the bodys organs
66
Why must blood that is pumped into the lungs be at a low pressure?
To prevent the capillaries from bursting.
67
Why do the kidneys need higher blood pressure than the lungs?
They carry out the pressure filtration of the blood..
68
Atria
Collecting chambers with thin walls that fill up with blood and pump it into the ventricles.
69
Ventricles
Pumping chambers with thick muscular walls that pump blood into the arteries.
70
Septum
The wall between the right and left sides of the heart, ensures that oxygenated and deoxygenated blood dont mix
71
Semilunar valves (Pulmonary), and Atrioventricular Valves (Systemic)
Ensure that blood circulates by preventing backflow.
72
Cardiac muscle
muscle tissue with the ability to contract without impulses.
73
Coronary vessels
Capillaries in the muscular walls of the heart that supply oxegyn and glucose for anaaerobic respiration.
74
75
Pacemaker
A region of specialized cardiac muscle cells in the wall of the right atrium that initiate each contraction. (The sinoatrial node)
76
Summarize the 3 stages of the cardiac cycle:
1) Walls of atrium contract, pushing blood into ventricles, while the semilunar valve is closed to fill them up with blood.
2) Walls of the ventricles contract powerfully which causes the AV valves to close and the SL valves to open allowing blood to be pumped out into the arteries. The Atari fill at the same time.
3) Vent
77
Outline the cardiac cycle:
- Atria walls contract, pushing blood into the ventricles through atrioventricular valves (open). Semilunar valves (closed) so the ventricles fill with blood.
- Ventricle walls contract, rising blood pressure, closes atrioventricular valves, opens semilunar valves, blood goes into arteries, atria simultaneously fill up.
- Ventricles stop contracting, blood pressure drops, semilunars close (preventing black flow from arteries).
- When blood pressure drops below atrial pressure, atrioventriculars open, blood entering atrium from veins then flows to fill ventricles. Next cycle begins when atria walls contract again.
78
What is each heartbeat initiated by?
The sinoatrial node - sends an impulse that spreads through atria walls, causing contraction.
79
What prevents the impulses in the heart from spreading directly into the walls of the ventricles?
A layer of fibrous tissue, they instead travel to the ventricles via a second node and a bundle of contracting fibers, which gives the atria time to pump blood before the ventricles contract.
80
Explain the movement of water from high to lower potential in xylem vessels:
- Root cells absorb water from soil, passed through walls by capillary action until its reaches xylem center of root.
- Enters epidermis cell by osmosis (which have high solute concentration).
81
Root pressure
A mechanism used when a plant is not transpiring.
82
Outline the process of water movement in xylem vessels:
- Root cells absorb water from the soil.
- Water moves through root cells to reach the center of the root (xylem).
- Water enters epidermis cells through osmosis.
- Epidermis cells have higher concentration and lower water potential compared to soil water.
- Water then moves from epidermis cells to nearby xylem vessels.
- Xylem vessels have lower water potential than endodermis cells.
