Chapter 8: Transport In Mammals Flashcards
Why do mammals need efficient transport systems?
Animals perform greater activities like muscle contraction and nervous impulses and therefore have a higher demand for oxygen.
What is the physiological reason for why larger animals need complex transport systems?
They have lower surface area to volume ratios
What are the different reasons for why a metabolically active cell might need might need an efficient transport system?
To supply oxygen for respiration, nutrients for metabolic processes and for the removal of wast products.
What is the cardiovascular system?
It is the system that pumps blood around mammals, composed of a heart and blood vessels that remain in a closed system.
What is systemic circulation?
Is is the circulation of blood around the body from the aorta to the vena cava. Systemic circulation excludes the pulmonary circulation which goes through the lungs.
What is the carotid artery?
They are blood vessels in the neck that supply the brain and head with blood.
What is the jugular vein?
It is a paired venous structure that collects blood from the brain, superficial regions of the face and brings it to the right atrium.
What is the subclavian artery?
It is the blood vessel that supplies the thorax (head, shoulder, neck and arms) with blood.
What is the subclavian vein?
It is the blood vessel that drains blood from the upper extremities.
What is the aorta?
It is the main blood vessel that carries blood away from the heart.
what is the pulmonary artery?
It is the main artery that carries deoxygenated blood away from the heart to the lungs in order to get oxygenated.
What is the hepatic artery?
is supplies oxygenated blood to the liver, pylorus of the stomach, duodenum, pancreas and the gall bladder.
What is the renal artery?
It is the artery that carried blood away from the heart tot he kidneys in order for it to get filtered.
What is the mesenteric artery?
It is the artery that takes blood to the major portion of the GIT, going through the mesentery.
What is the iliac artery?
It carries blood to the lower limbs
What is the iliac vein?
Carries blood away from the the lower limbs
What is the Renal Vein?
It is the vein that carries blood away from the kidneys after filtration back to the the heart.
What is the hepatic portal vein?
Is the vein that conveys blood to the liver from the spleen stomach, stomach, pancreas and intestine.
What is the hepatic vein?
The hepatic veins are the veins that drain de-oxygenated blood from the liver into the inferior vena cava
What is the vena cava?
It is the main vein that brings back deoxygenated blood to the heart.
What is the pulmonary vein?
it is the vein that brings back oxygenated blood from the lungs to the heart.
What does the pulmonary circulation mean?
It involves the pulmonary artery and pulmonary vein that would bring blood to the lungs
What does the term ‘Double Circulation’ mean?
It is the combination of the pulmonary circulation and the systemic circulation where the blood flows through the hear twice in one circulation.
What is the basic difference between arteries and veins?
Arteries carry blood away from the heart and veins carry blood towards the heart.
Name the three layer that an artery is composed of.
- The Endothelium (tunica intima)
- Tunica media
- Tunica Externa
Describe the composition of the three layer of the heart.
Tunica intima: Made of squamous epithelial cells that are arranged in a jigsaw fashion that reduces friction.
Tunica Media: Made of smooth muscle, collagen anf elastic fibres
Tunica Externa: Elastic fibres and collagen fibres
Why is the arteries really thick and elastic?
So that it can carry blood at high pressures
What are the dimensions of the Aorta?
2.5 cm diameter
2 mm thick wall
Describe the composition of the tunica media the further away web go from the heart.
The tunica media usually just has elastic fibres that allow stretching.
however, the further away we go from the heart, the more muscle fibre we have.
How the arteries smoothen the flow of blood?
The blood is pumped in pulses where the walls stretch to reduce the pressure and then recoil to increase the pressure to push it down.
How do the arteries reduce the likelihood of bursting?
the stretching and recoiling maintain the pressure from the the aorta.
What is the role of the arterioles?
It regulates the volume of blood flowing into the tissues based on the demand by dilating and constricting.
What allows the dilation and constriction of the arterioles?
The presence of smooth muscle.
Describe and explain the changes in blood pressure from the arteries to the arterioles?
Blood pressure drops from the arteries to the arterioles due to the increased SA: Volume ratio.
What are capillaries?
They are tiny blood vessels that go near the tissue to supply nutrients by forming capillary beds around the tissue.
How are the capillaries adapted to get as close to the tissue as possible?
They are made of only endothelial cells that allows blood to be brought as close to the tissue as possible.
What is the function of the endothelial gaps in the capillaries?
They allow components of blood to seep through into the spaces between the cell.
How is blood returned back to to the heart?
The capillaries will join to form venules that will eventually join to form veins, that will eventually reach the heart via the vena cava.
Why do vein have really thin tunica media?
Because the blood pressure in the veins is really low.
How does the the veins flow blood back to the heart if the pressure is really low?
The veins form semilunar valves that form on the endothelium the pump the blood back to the heart.
What are the blood pressure around the circulatory system in mm Hg?
Aorta 120 Arteries 85 Arterioles 35 Capillaries 10 Veins 5
What is the blood pressures around the circulatory system in kPa?
Aorta 16
Arteries 11.3
Arterioles 4.7
Capillaries 1.3
What is the general composition of blood?
It is mainly composed of plasma
It also has cells floating in it with glucose and waste products suspended
What is tissue fluid?
It is the almost colourless fluid that fills the spaces between body cells and it forms from the leakage of blood capillaries and most of it eventually collects into the lymph vessels where it will form lymph
Describe the composition of tissue fluid and explain why some components of blood may not get in.
Tissue fluid contains proteins and WBC’s;
Other things like RBC’s and proteins are much too large
What are the pressures that cause the net loss of plasma from the capillaries into tissue fluid?
Capillary pressure pushing it out and water pressure from the the solutes trying to push it back in
The net loss prevents too much of the plasma from leaking which could have lead to an oedema.
What is an Oedema?
it is the build up of fluid into tissue due to the excess pressure that has build up in the arteries; the arterioles have to regulate the pressure in order to reduce excess fluid loss.
What is the function of tissue fluid?
It helps to maintain homeostasis and the internal cellular environment; including glucose, water, pH, metabolic waste and temperature
What is lymph?
it is when some of the tissue fluid that leaked out moves into the lymphatic vessels
What are lymph vessels?
They are blind ending and have valves in them that allow the inflow, but not the outflow of tissue fluid.
Why does the lymph have to remove protein?
because the capillaries are not adapted to do that; accumulation of protein will lead to an increase concentration gradient that could lead to an imbalance and eventually and oedema.
Describe the composition of lymph between the GIT and liver
The lymph from the liver has high protein concentration and the lymph from the the GIT has higher fat concentration gradient.
Why does the subclavian vein need lots of smooth muscle?
The movement of lymph through the subclavian vein very slow and requires contraction.
What are lymph nodes?
They are node around the lymphatic system that have WBC’s, antibodies and so when the lymph passes, bacteria is killed.
What is the function red blood cells?
They allow oxygen to get from the lungs to the the respiring tissue
Why are red blood cells made?
Thy are made in the bone marrow in adults and babies and in the liver for fetuses
Where do red blood cells rupture?
They rupture in clots in the spleen as they age
What are the adaptations of the Red blood cells and how do they help the transport of oxygen?
- Biconcave disc: High SA: V ration
- Small: So that the capillaries can be made small and the haemoglobin can get close to the cells
- Flexible: The mesh like structure allows the RBC’s to squash so that they can get into capillaries smaller then their diameter
- No other organelles: So that haemoglobin has more room/ more haemoglobin
How do WBC’s differ from RBC’s?
- Presence of a nucleus
- Larger
- Regular/ irregular shape
What are the two types of WBC’s and what are their roles? WHat are their characteristic features?
- Phagocytes: Phagocytosis; lobed nucleus; granular cytoplasm
- Lymphocytes: Production of antibodies; smaller, round nucleus and less cytoplasm
What is haemoglobin?
to transport oxygen
How much oxygen can each haemoglobin carry? What about its structure allows it to carry this amount?
4 oxygen molecules
They have 4 haem groups in each of the 4 polypeptides
What is the haemoglobin dissociation curve?
is the variation of the saturation haemoglobin at different partial pressures around the circulatory system
Describe the difference of saturation between different types of muscle and tissue.
- Respiring muscle tissue: las low saturation at a low partial pressure
- Lungs: High partial pressure and high saturation
Why does the haemoglobin dissociation curve have an s shape to it?
the Allostery of Haemoglobin makes the curve steep as the oxygen combined to it increases as the pressure begins to increase
What is meant by the Bohr shift?
It is the idea that the release of the of oxygen is not only affected by the partial pressure but also by the pressure of CO2
What are the reactions that re a result from the carbonic anhydrase enzyme?
CO2 + H2O -> H2CO3
H2CO3 H+ + HCO3-
How does haemoglobin act as a buffer
It picks up the H+ ions, preventing the blood pH from getting too low
How does the Bohr shift work?
The release of carbon dioxide from respiration will encourage release of oxygen in the Bohr effect
Therefore, high CO2 concentrations reduce the CO2 saturation
How is CO2 transported in the blood?
As a HCO3- ion
What is carboaminheamoglobin?
It is the form of CO2 that does not become HCO3- ion, where they bind to the terminal amine group
What happens to the the CO2 in the blood at the alveoli?
The low CO2 concentration in the alveoli cause CO2 to diffuse out and HCO3- and the H+ become CO2 again and haemoglobin is free.
What is the problem with carbon monoxide?
Haemoglobin readily combines with CO, which makes carboxyhaemoglobin, and due to the stability of CO, it stays combined for long and results is death by asphyxiation
What is the treatment for carbon monoxide poisoning?
Administer O2 and CO2 mixture
Why is O2 and CO2 administered to a patient that has CO poisoning?
O2: stimulate haemoglobin to combine with it
CO2: to increase breathing rate
Describe the difference of blood oxygen saturation at different altitudes.
Sea level: the 20 kPa -> 13 kPa in the lungs -> 100% sat
High Altitude: 10 kPa -> 5.3 kPa in lungs -> 70% sat
What are the problems of high altitude
Breathlessness -> Altitude sickness
What are the symptoms pf altitude sickness?
High breathing rate High breathing depth Dizziness Weakness Brainlessness
Why does altitude sickness cause a brainlessness feeling
The arterioles dilate -> the fluid leaks due to high pressure -> causes disorientation
How do people who live at high altitudes adapt to the condition?
^ RBC count
^ Lung capacity
^ haemoglobin
What is the heart made of?
Cardiac muscle
What is cardiac muscle?
Tightly bound muscle by the cell surface membrane that allows electrical excitation
What is an intercalated disc?
It binds the cardiac muscle together and allows the passing of signals
What are the different atrioventricular valves?
Left: Mitral/ Bicuspid
Right: tricuspid
What is the cusp?
it is a triangular segment that open and close valves
What is the papillary muscle?
It is the muscle attached to the atrioventricular valve. It contracts
What are the main structures of the heart?
Aorta Pulmonary artery Vena cava Pulmonary veins Coronary artery Atrium Ventricle
What are the 3 stages of the cardiac cycle?
- Atrial Systole
- Ventricular Systole
- Ventricular diastole
What is atrial systole?
It is when Atria contract to push the blood into the ventricles
iWhat is ventricular systole?
it is when the ventricles contract to push blood into the Aorta and the pulmonary Artery; semilunar valves open
What is ventricular diastole?
The Atria and the ventricle relax, valves push shut and the blood flows in from the veins
Why does the left ventricle have a lot of muscular thickening?
It need force to supply blood to all of the organs
What are some body parts that require high pressure?
- The Brain
- Ultrafiltration in the kidneys
- The superficial body parts
What does myogenic mean?
It means that the cardiac muscles can contract and expand without the need of any impulses.
Why does the heart need a coordinating system?
to ensure that all of the cardiac muscle will contract and expand in sequence
What is the sinoatrial node?
It is a patch of muscle in the wall of the right atrium of the heart, whose intrinsic rate of rhythmic contraction is faster than that of the cardiac muscle, and from. Which waves of excitation spread to the rest of the heart to initiate its contraction during the cardiac cycle.
What is the atrioventricular node?
it is a patch of tissue in the septum of the heart, through which the wave of electrical excitation is passed from the atria to the Purkyne tissue.
Why is the electrical excitation delayed for the ventricle?
So that it can pump after the blood has arrived and so that the circulation is regulated.
What is the Purkyne tissue?
It is the area of tissue in the septum of the heart that conducts the wave of excitation from the atria to the base of the ventricles.
What is fibrillation?
It is when the electrical impulses that coordinate the heart becomes chaotic and the contractions and relaxation is not coordinated
What is an ECG?
An electrocardiogram is a graph of voltage against time that measures the electrical excitation which flows through the heart muscles.
Describe a pulse of an ECG
Small bump: Activity of the atrial wall
Large spike and decline: The activity of the ventricle walls
Slightly smaller bump: Recovery of the ventricle walls.
