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A level Biology > Chapter 8 - Transport in Animals > Flashcards

Chapter 8 - Transport in Animals Flashcards

(48 cards)

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1
Q

Why are specalised transport systems important multicellular organisms?

A

High metabolic demands
Small SA:V so substances can’t just diffuse in and out and get to all of the organism
Hormones and enzymes can be one place but needed in another place
Food is digested in one organ but the products are needed in ever cell across the body
Waste products from metabolism need to be removed from cells, then removed in certain organs

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2
Q

What is a circulatory system?

A

A system which carries gases, nutrients, waste products and hormones around the body

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3
Q

What do most circulatory systems have in common?

A

A transport medium that circulates around the system (e.g. blood)
Vessels to carry the transport medium
A pumping mechanism to move the transport medium around the system?

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4
Q

What is a mass transport system?

A

When substances are transported in a mass of fluid with a mechanism for moving the fluid around the body

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5
Q

What is an open circulatory system?

A

Very few vessels to contain transport medium
Pumped from heart to body cavity of animal
Usually found in invertebrate animals
Open body cavity called haemocoel
Transport medium called haemolymph

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6
Q

Why are open circulatory systems less efficient?

A

Due to the transport medium being free flow throughout most of the body cavity, it is difficult to maintain a steep concentration gradient for efficient diffusion

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7
Q

What is a closed circulatory system?

A

Blood is enclosed in blood vessels and doesn’t come into direct contact with body cells
High pressure
Blood returns back to the heart
Most contain a blood pigment essential for carrying respiratory gases

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8
Q

What is a single closed circulatory system?

A

Blood leaves the heart, goes around the body and comes back to the heart
Blood only needs to enter the heart once to complete a full circulation
Blood pressure is very low so exchange processes are slow and inefficient

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9
Q

What is a double closed circulatory system?

A

Blood is pumped from heart to lungs to heart
Then blood is pumped from heart to body to heart
The blood has to travel through the heart twice to complete a full circuit
High blood pressure and fast blood flow can be maintained to improve efficiency of exchange

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10
Q

What are elastic fibres in blood vessels?

A

Composed of elastin
Can stretch and recoil
Provide blood vessel walls with elasticity

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11
Q

What is smooth muscle in blood vessels?

A

Can contract or relax to change the size of the lumen

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12
Q

What is collagen in blood vessels?

A

Provides structural support
Maintains shape and volume of blood vessel

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13
Q

What is the order of blood vessels from aorta to vena cava?

A

Artery
Arteriole
Capillary
Venule
Vein

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14
Q

What is an artery?

A

Carries oxygenated blood from heart to organs (except for pulmonary artery and umbilical artery)
Blood under high pressure
Can vasoconstrict and vasodilate
Tough collagen outer layer
Thick muscle layer
Thick elastic layer
Smooth endothelium layer to prevent friction between erythrocytes

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15
Q

What is an arteriole?

A

Link arteries to capillaries
Less elastic in walls
More smooth muscle
Lower blood pressure
Muscle contracts and relaxes to control blood flow

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16
Q

What is a capillary?

A

Tiny vessels to carry out gas exchange
Can be oxygenated or deoxygenated
Endothelium lining layer only one cell thick

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17
Q

What is a venule?

A

Connect capillaries with veins
Very thin walls with small amounts of muscle

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18
Q

What is a vein?

A

Caries deoxygenated blood (except pulmonary vein and umbilical vein)
Have valves to prevent back blood of blood
Very low blood pressure compared to arteries
Tough collagen outer layer
Thin muscle layer
Thin elastic layer
Thin endothelium - smooth to prevent friction
Large lumen

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19
Q

What are the functions of the blood?

A

Transporting many types of molecules such as gases for/from respiration, digested food, hormones, cells, antibodies and platelets
Maintaining a constant body temperature
Minimise pH changes by acting as a buffer

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20
Q

What are the components of the blood?

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A

Red blood cells (erythrocytes)
White blood cells (leukocytes)
Platelets
Plasma

21
Q

What are the functions red blood cells?

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A

Transport oxygen and play a role in transporting carbon dioxide (haemoglobin)

22
Q

What are the functions of white blood cells?

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A

Different types of white blood cells play different roles on the organisms immune system

23
Q

What are the functions of platelets?

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A

Cell fragments which play a part in the clotting process

24
Q

What are the functions of plasma?

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A

Liquid medium which carries dissolved substances

25
What is tissue fluid?
Similar to blood plasma Doesn't contain plasma proteins or most of the cells Formed by plasma leaking from capillaries Surrounds cells in the tissue and supplies them with oxygen and required nutrients Waste products from metabolism can be returned to capillaries Low hydrostatic pressure Higher oncotic pressure Very few white blood cells Contains water and dissolved solutes
26
What is lymph fluid?
The 10% of fluid that isn't returned to capillaries is returned as lymph via the lymphatic system Similar to tissue fluid, but contains more white blood cells White blood cells collect in large quantities in the lymph nodes to fight infection Low hydrostatic pressure Higher oncotic pressure Contains water and dissolved solutes
27
What is hydrostatic pressure?
Pressure of fluid on the capillary walls, usually forcing plasma out of the circulatory system
28
What is oncotic pressure?
Osmotic pressure from proteins in the blood plasma that draws water into the circulatory system
29
How does pressure affect the movement of blood?
Tissue fluid, own hydrostatic pressure and oncotic pressure + solutes have an influence Hydrostatic pressure of blood pushes fluid out of capillaries into tissues Oncotic pressure of blood pulls water back into blood
30
How does pressure affect the movement of tissue fluid?
Hydrostatic pressure of tissue fluid pushes fluid back into capillaries Oncotic pressure of tissue fluid pulls water from blood to tissue fluid
31
Why is haemoglobin needed?
Carries oxygen as it isn't soluble in water Otherwise there wouldn't be enough oxygen to meet the body's demand Absorbs oxygen to transport it around the body
32
What is the structure of haemoglobin?
Quaternary globular protein 2 alpha, 2 beta chains Each chain contains a haem group (contains iron) Iron has a high affinity for oxygen Each oxygen can carry 4 oxygen molecules
33
What is affinity?
Attraction (to oxygen)
34
How is oxygen transported?
Joins with haemoglobin to form oxyhaemoglobin (reversible reaction) Oxygen joining = association Oxygen leaving = dissociation Hb + 4O2 <-> HbO8
35
How does oxygen affinity change around the body?
Depends on external conditions Partial pressure of oxygen changes (pO2) Increases oxygen concentration = higher pO2 = high oxygen affinity (e.g. in the lungs) Decreased oxygen concentration = lower pO2 = low oxygen affinity (e.g. in the body cells)
36
How does oxygen affinity affect associating and dissociating?
High oxygen affinity = Oxygen associates into the red blood cells Low oxygen affinity = Oxygen dissociates out of the red blood cells
37
How is haemoglobin relevant to carbon dioxide transport?
Carbon dioxide needs to be excreted 5% gets dissolved into blood plasma 10% binds to Hb and forms carbaminohaemoglobin 75% from HCO3- which is formed in the RBC then gets transported in the blood plasma
38
How does carbon dioxide change to be carried as hydrogen carbonate?
1. Carbon dioxide diffuses in RBC 2. Carbon dioxide converts to carbonic acid by enzyme carbonic anhydrase 3. Carbonic acid dissociates into a H+ ion and hydrogen carbonate ion 4. Hydrogen carbonate diffuses out of RBC down the concentration gradient and combines with sodium ions in the plasma 5. Chloride ion enters RBC (chloride shift) to maintain the electrochemical neutrality 6. H+ combines with HB to form haemoglobinic acid (HHb) which prevents the H+ ion from decreasing RBC pH
39
What is the Bohr effect?
Partial pressure of carbon dioxide rises Hb gives up oxygen easier
40
What is the heart?
Made up of cardiac muscle Has coronary arteries covering it to supply it with oxygen (if blocked causes angina or a heart attack/myocardial infarction)
41
Why does the valves have tendinous cords?
Prevents the valves from turning inside out during ventricular wall contractions
42
What is the order of the cardiac cycle starting at the right atrium?
Right atrium Tricuspid valve Right ventricle Semilunar valve Pulmonary artery Lungs Pulmonary vein Left atrium Bicuspid valve Left ventricle Semilunar valve Aorta Body Vena cava
43
What is the cardiac cycle?
Sequence of events in one full beat of the heart Averagely 0.8s in humans
44
What is systole?
Period of contraction
45
What is diastole?
Period of relaxation
46
How is blood pumped in the heart?
Pressure is exerted by blood causes pressure changes which moves the valves Heart muscles contract and relax to force blood into different chambers/vessels in the heart
47
What are the 3 parts of the cardiac cycle (contractions)?
Diastole Atrial systole Ventricular systole
48
What is the function of the valves?
Ensures blood flows in the correct direction Increased pressure behind the valves forces them open Decrease pressure through the valves forces them shut

A level Biology (25 decks)

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