Mass Transport In Animals Flashcards
(108 cards)
1
Q
Why do multicellular organisms need transport systems?
A
To transport nutrients and oxygen and remove waste products efficiently due to larger size and higher metabolic rate
Compared to single-celled organisms, multicellular organisms have larger diffusion distances.
2
Q
What is a single circulatory system?
A
A system where blood passes through the heart once per circuit
3
Q
What is a double circulatory system?
A
A system where blood passes through the heart twice per circuit
4
Q
What characterizes an open circulatory system?
A
Blood flows freely through body cavity and returns to heart through valves
5
Q
What is a closed circulatory system?
A
Blood is enclosed in vessels
6
Q
What is the function of arteries in a closed circulatory system?
A
To distribute oxygenated blood
7
Q
What is the function of veins in a closed circulatory system?
A
To return deoxygenated blood to the heart
8
Q
What type of circulatory system do mammals have?
A
A closed, double circulatory system
9
Q
What are the two main divisions of the mammalian circulatory system?
A
- Systemic system
- Pulmonary system
10
Q
What happens in the systemic circulatory system?
A
Oxygenated blood is pumped out of the heart via the aorta to most body tissues
11
Q
How is deoxygenated blood returned to the heart in the systemic system?
A
Via the vena cava from the body tissues
12
Q
What happens in the pulmonary circulatory system?
A
Deoxygenated blood is pumped out of the heart via the pulmonary artery to the lungs
13
Q
How is oxygenated blood returned to the heart from the lungs?
A
Via the pulmonary vein
14
Q
What are the five main types of blood vessels in the mammalian circulatory system?
A
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
15
Q
What is the primary function of arteries?
A
Carry blood away from the heart
16
Q
What do arterioles do?
A
Carry blood from arteries into capillaries
17
Q
What is the role of capillaries?
A
Site of diffusion between blood and body tissues
18
Q
What is the function of venules?
A
Carry blood from capillaries into veins
19
Q
What do veins do?
A
Return blood to the heart
20
Q
How are arteries adapted to carry blood at high pressure?
A
- Collagen for strength
- Elastic fibres for stretch and recoil
- Thick smooth muscle layer
21
Q
What is the function of collagen in arteries?
A
Provides strength to prevent the vessel from bursting and to maintain vessel shape
22
Q
What do elastic fibres in arteries do?
A
Allow arteries to stretch and recoil to minimize changes in pressure
23
Q
How does the thick smooth muscle layer in arteries function?
A
Contracts/relaxes to constrict/dilate the lumen and control blood flow
24
Q
What distinguishes arterioles from arteries?
A
Arterioles are smaller with a comparatively larger lumen and more smooth muscle
25
What is vasoconstriction?
Smooth muscle contracts, constricting the blood vessel and decreasing blood flow
26
What is vasodilation?
Smooth muscle relaxes, dilating the blood vessel and increasing blood flow
27
What are the adaptations of capillaries?
* Very narrow lumen
* Thin walls
* Highly branched
28
Why is the lumen of capillaries very narrow?
Allows red blood cells to be close to body cells
29
Why are the walls of capillaries thin?
Allows substances to be exchanged across a short distance by diffusion
30
What is the advantage of capillaries being highly branched?
Provides a large surface area for diffusion
31
How are veins adapted to carry blood towards the heart?
* Collagen for strength
* Little smooth muscle and elastic fibre
* Valves
32
What is the function of valves in veins?
Prevent backflow of blood when veins are squeezed by surrounding skeletal muscle
33
What is the structural similarity between pocket valves in veins and heart valves?
Both are designed to prevent backflow, but pocket valves are controlled by skeletal muscle
34
What are venules and how do they differ from veins?
Venules are smaller than veins, with very thin walls and very little smooth muscle
35
What is blood?
Blood is the fluid that transports substances around the human circulatory system.
36
What are the components of blood?
* Plasma
* Red blood cells
* White blood cells
* Platelets
37
What is the primary function of plasma?
Plasma is mostly water and transports substances in solution.
38
What do red blood cells do?
Red blood cells carry oxygen.
39
What is the role of white blood cells?
White blood cells are immune cells.
40
What is the function of platelets?
Platelets are involved in clotting.
41
List three functions of blood.
* Transports oxygen and carbon dioxide
* Transports nutrients from digestion
* Transports waste for excretion
42
What is tissue fluid?
Tissue fluid (interstitial fluid) fills spaces between cells (interstitial space).
43
What is the role of tissue fluid?
It provides cells with nutrients and oxygen while removing waste products.
44
How does tissue fluid help the immune system?
Tissue fluid helps fight infection as it forms part of the immune response.
45
What is one key difference between tissue fluid and plasma?
Tissue fluid has no red blood cells.
46
What is another difference between tissue fluid and plasma?
Tissue fluid has fewer proteins.
47
How is tissue fluid formed?
Tissue fluid is formed from the blood flowing through capillaries.
48
What happens at the arteriole end of capillaries?
A high hydrostatic pressure forces fluid out of capillaries.
49
What occurs at the venule end of capillaries?
The hydrostatic pressure is lower, and proteins exert a high oncotic pressure.
50
What is lymph?
Lymph is the fluid that flows around the lymphatic system via lymph vessels.
51
How does lymph compare to tissue fluid?
Lymph has less oxygen and nutrients, more fatty acids, and more white blood cells (lymphocytes).
52
How is lymph formed?
Lymph is formed from tissue fluid that drains into lymph vessels.
53
How is lymph transported around the body?
Lymph is transported through lymph vessels by muscle contractions.
54
What is the purpose of lymph nodes?
Lymph nodes filter pathogens from lymph.
55
Where is lymph eventually returned?
Lymph is eventually returned to the blood.
56
Fill in the blank: Tissue fluid has _______ white blood cells compared to plasma.
fewer
57
True or False: Lymph has a higher concentration of nutrients than tissue fluid.
False
58
How does oxygen enter the body?
Oxygen enters the lungs from atmospheric air
59
What is the role of haemoglobin in oxygen transport?
Haemoglobin in red blood cells transports oxygen to body cells
60
What is formed when oxygen binds to haemoglobin?
Oxyhaemoglobin
61
How many oxygen molecules can one haemoglobin molecule carry?
4 oxygen molecules
62
Where does oxygen dissociate from haemoglobin?
At body cells
63
What does haemoglobin saturation depend on?
Oxygen concentration or partial pressure of oxygen (pO2)
64
What units are used to measure partial pressure of oxygen?
Kilopascals (kPa)
65
What happens to haemoglobin saturation at higher pO2?
Haemoglobin has a high affinity for oxygen and binds with it
66
What happens to haemoglobin saturation at lower pO2?
Haemoglobin has a low affinity for oxygen and releases it
67
What is the cooperative nature of oxygen binding?
When haemoglobin binds with one oxygen, it changes shape to bind more easily
68
How does fetal haemoglobin differ from adult haemoglobin?
Fetal haemoglobin has a higher oxygen affinity than adult haemoglobin
69
Why does fetal haemoglobin have a higher affinity for oxygen?
To obtain oxygen from the mother's blood
70
What is the Bohr effect?
The decreased affinity for oxygen in haemoglobin when carbon dioxide is present
71
What effect does higher pCO2 have on haemoglobin saturation?
Causes haemoglobin to release oxygen
72
What is the significance of the Bohr effect?
It enables active tissues to receive more oxygen
73
How is carbon dioxide transported in the blood?
A small percentage is dissolved in plasma, some bound to haemoglobin, most as hydrogen carbonate ions
74
What happens to CO2 in red blood cells?
It is converted into hydrogen carbonate ions
75
What enzyme catalyzes the formation of carbonic acid from CO2 and water?
Carbonic anhydrase
76
What occurs when carbonic acid dissociates?
It forms H+ and HCO3- ions
77
What is formed when H+ binds to haemoglobin?
Haemoglobinic acid
78
What is the chloride shift?
HCO3- ions leave red blood cells while chloride ions enter
79
What happens at the lungs concerning CO2?
HCO3- and H+ reform CO2 which diffuses out of the body
80
Fill in the blank: Haemoglobin can carry ____ oxygen molecules.
4
81
True or False: Fetal haemoglobin has a lower affinity for oxygen than adult haemoglobin.
False
82
What are the four chambers of the human heart?
Left atrium, right atrium, left ventricle, right ventricle
## Footnote
The heart consists of two atria and two ventricles.
83
What is the primary function of the atria?
To collect blood from blood vessels (veins)
## Footnote
Atria are the top chambers of the heart.
84
What is the primary function of the ventricles?
To pump blood into blood vessels (arteries)
## Footnote
Ventricles are the bottom chambers of the heart.
85
What type of blood does the left side of the heart contain?
Oxygenated blood
## Footnote
The right side contains deoxygenated blood.
86
What are the two separate pumping mechanisms of the heart designed to prevent?
Blood pressure drops in the lungs and a single pump would slow blood flow to body cells
## Footnote
Two pumps increase pressure before blood circulation.
87
What structure separates the two sides of the heart?
The septum
## Footnote
The septum prevents mixing of oxygenated and deoxygenated blood.
88
What is the role of valves in the heart?
To prevent backflow of blood in the wrong direction
## Footnote
Valves ensure unidirectional blood flow.
89
Where is the tricuspid valve located?
Between the right atrium and right ventricle
## Footnote
It is one of the atrioventricular valves.
90
Where is the bicuspid (mitral) valve located?
Between the left atrium and left ventricle
## Footnote
It prevents backflow into the atrium when the ventricle contracts.
91
What do the semi-lunar valves prevent?
Backflow of blood into the ventricles when they relax
## Footnote
These valves are located between the ventricles and the arteries.
92
What blood vessel moves oxygenated blood into the left atrium from the lungs?
The pulmonary vein
## Footnote
It connects the lungs to the heart.
93
What blood vessel moves deoxygenated blood into the right atrium from the body?
The vena cava
## Footnote
It includes the superior and inferior vena cava.
94
What blood vessel moves oxygenated blood from the left ventricle to the body?
The aorta
## Footnote
It is the largest artery in the body.
95
What blood vessel moves deoxygenated blood from the right ventricle to the lungs?
The pulmonary artery
## Footnote
It carries blood away from the heart to the lungs.
96
How does the thickness of the ventricular walls compare to the atria walls?
Ventricles have thicker walls than atria
## Footnote
This is due to their different functions.
97
Why do the ventricles require thicker walls than the atria?
To generate enough pressure to pump blood a long distance out of the heart
## Footnote
Atria only pump blood a short distance.
98
What is the cardiac cycle?
The sequence of contraction and relaxation of the cardiac muscle in the heart
## Footnote
It includes three main stages.
99
What are the three main stages of the cardiac cycle?
* Atrial systole
* Ventricular systole
* Diastole
## Footnote
Each stage has specific actions and changes in pressure.
100
What happens during atrial systole?
The ventricles relax, and the atria contract, increasing atrial pressure
## Footnote
Blood flows into the ventricles during this stage.
101
What occurs during ventricular systole?
The ventricles contract, and the atria relax, increasing ventricular pressure
## Footnote
Blood flows into the arteries during this stage.
102
What happens during diastole?
The ventricles and atria relax, allowing passive blood flow into the atria
## Footnote
The semi-lunar valves close during this stage.
103
What does it mean that cardiac muscle is myogenic?
The contraction of cardiac muscle initiates within the heart itself
## Footnote
This is different from skeletal muscle, which requires neural stimulation.
104
What initiates the heartbeat?
Sinoatrial node (SAN)
## Footnote
It stimulates the atria to contract.
105
What role do collagen fibres play in the heart's electrical conduction system?
They prevent direct electrical flow from atria to ventricles
## Footnote
This allows for coordinated contraction.
106
What is the function of the atrioventricular node (AVN)?
It picks up electrical activity from the SAN and imposes a slight delay
## Footnote
This delay allows the atria to finish contracting before the ventricles start.
107
What does the Bundle of His do?
Receives electrical activity from the AVN and conducts it to the apex of the heart
## Footnote
It plays a crucial role in coordinating heart contractions.
108
What are Purkyne fibres responsible for?
Causing the right and left ventricles to contract from the bottom upwards
## Footnote
This ensures efficient blood ejection from the ventricles.
