Module 3: Section 2 - Transport in Animals Flashcards
why cant multicellular organisms rely on solely diffusion
-low SA:V
-higher metabolic rate
-relatively big
-Many multicellular organisms are also very active so a large number of cells are respiring very quickly
what are the types of circulatory systems
-single
-double
-closed
-open
what type of circulatory system do fish and mammals have
fish=single closed
mammals=double closed
what happens in a single circulatory system
blood only passes through the heart once for each complete circuit of the body
what happens in a double circulatory system
the blood passes through the heart twice for each complete circuit of the body
what does the systemic system do
sends blood to the rest of the body
what does the pulmonary system do
sends blood to the lungs
what is a closed circulatory system
its when the blood is enclosed within the blood vessels
What is an advantage of a double circulatory system
heart can give the blood an extra push between the lungs and the rest of the body so blood travels faster and oxygen is delivered to the tissues more quickly
what is an open circulatory system
it is when blood is not enclosed in the blood vessels all the time and it instead flows freely through the body cavity
what are the blood vessels we need to know about
-arteries
-capillaries
-Veins
-venules
-arterioles
what is the function of the arteries
carry blood away from the heart to the body
what is the arteries structure why is it beneficial
-thick elastic tissues(elastin) to help arteries to stretch when blood is pumped out of the heart and recoil between heartbeats to maintain high pressure
-inner lining(endothelium) is folded, allowing the artery to expand and maintain high blood pressure
-thick muscular walls of smooth muscle and elastin
-narrow lumen
-no valves as blood flows at high pressure so wont backflow
-collogen to maintain its structure
what is the function of the veins
take blood from the body back to the heart under low pressure
what is the veins structure why is it beneficial
-collogen to maintain its structure
-thinner walls as blood is flowing through them at lower pressures and so higher volumes of blood can flow through them
-The large lumen reduces the resistance to blood flow, which helps blood return to the heart even though it’s under lower pressure.
-valves to prevent backflow
-smooth endothelium: smooth lining ensures that blood flows efficiently without forming clots.
what is the function of the capillaries
to enable the exchange of oxygen, nutrients, and waste products between the blood and surrounding tissues through their thin walls.
what is the structure of the capillaries
- single layer of endothelium cells (one cell thick) for short diffusion distance
-narrow lumen to allow close contact with tissues
-many capillaries (capillary network) increase the surface area
what do arteries branch off into
arterioles
what do arterioles branch off into
capillaries
what do capillaries branch off into
venules
what do venules branch off into
veins
what is the function of the venules
to collect deoxygenated blood from the capillaries and transport in to the veins
what is the function of the arterioles
to regulate blood flow from arteries into capillaries by constricting or dilating in response to the body’s needs.
what is the venules structure
small amounts of smooth muscle and elastic tissue
what is the arterioles structure
thick walls with higher proportions of thick muscle
what is hydrostatic pressure
pressure exerted by the blood against the walls of blood vessels, particularly in capillaries, which helps drive the movement of fluids out of the bloodstream and into surrounding tissues.
What is oncotic pressure
is the pressure exerted by proteins, particularly albumin, in the blood plasma, which helps pull water into the bloodstream from surrounding tissues.
what is tissue fluid
is the fluid that surrounds cells in tissues and is made from substances that leave the blood tissue e.g. red blood cells
Give the process of pressure filtration
1) blood is pushed from the arteries to the capillaries which causes the hydrostatic pressure in the capillaries to be greater than in the tissue fluid
2)The pressure gradient forces small fluid and etc out of the capillaries through the pores, forming tissue fluid
3) as the fluid leaves the hydrostatic pressure reduces in the capillaries, so hydrostatic pressure is lower at the capillary bed close to the venules
4)the oncotic pressure is generated by plasms proteins like albidum which lowers the water potential in the capillaries so water re enters the capillaries via osmosis
What is the function of valves
They prevent backflow
where does excess tissue fluid go
gets returned to the blood through the lymphatic system, which is a kind of drainage system made up of lymph vessels
Describe the process of the lymphatic system
1) The smallest lymph vessel are the lymph capillaries
2)excess tissue fluid passes into the lymph vessels and once inside it is called the lymph
3) Valves in the lymph prevent backflow
4)Lymph gradually moves towards the main lymph vessels in the thorax
Where are the atrioventricular valves and the semi- lunar valves
-atrioventricular are between the atrium and ventricle
-semi-lunar valves are between the ventricles pulmonary artery and aorta
What is the cardiac cycle
the flow of blood from the lungs to the heart and around the body
What happens in the first stage of the cardiac cycle
-blood from the lungs flows into the left atrium and blood from the body flows into the right atrium and this occurs simultaneously #
-the atria contracts, increasing the pressure in the atria
-the blood in the atria is forced into the ventricles
-The ventricles are relaxed and fill with blood
What happens in the second stage of the cardiac cycle
-atria relaxes(diastyole) and the ventricle contracts(systole), causing pressure in the ventricle to increase
- Pressure causes the atrioventricular valve to close
-blood in the ventricles is forced out of the heart through the pulmonary artery and aorta
what happens in the final stage of the cardiac cycle
-Blood in the pulmonary artery and aorta is at high pressure which shuts the semi lunar valves so no backflow
-Both the ventricle and atria relax and the atrioventricular valves reopen and blood flows to ventricles and atria
what is the ‘lub’ and ‘dub’ sound
the lub is the atrioventricular valve closing and the dub is the semi-lunar valve closing
How do doctors diagnose heart problems
They compare their patients ECG’s with a normal ECG
What does ECG stand for
Electrocardiograph
What does an ECG do
records the electrical activity of the heart
What is a P wave caused by
contraction (depolarisation) of the atria
What is the main peak of the heartbeat with the dips at either side called
QS complex, its caused by contraction (depolarisation) of the ventricles
What is the T wave caused by
relaxation (repolarisation) of the ventricles
What does the height of the wave indicate
how much electrical charge is passing through the heart so a bigger wave means more electrical charge , so a bigger wave means a stronger contraction
What is it called when a heartbeat is too fast
tachycardia
What is it called when there is an extra heartbeat with a longer than normal gap
ectopic heartbeat
What is it called when there is an irregular heartbeat and the atria loose their rhythm
atrial fibrillation
What is it called when the heartrate is slowed and spaced evenly
Bradycardia
What is it called when the heartbeat is rapid ,wide irregular ventricular complexes
Ventricular fibrillation
What is the structure of haemoglobin
-large globular protein
-Quaternary structure
-Made up of 4 polypeptide chains ( 2 alpha chains and 2 beta chains)
What does SAN stand for
sinoatrial node
What is a haem group and why is it vital when talking about haemoglobin
-It is a prosthetic group that is attached to the protein
-It is vital when talking about haemoglobin as it has an iron ion which gives the haemoglobin its red colour
Why is the partial pressure of oxygen so important
it determines weather oxygen binds to the haemoglobin
What is affinity
How easily something can bind to oxygen
How many oxygen molecules can each haemoglobin carry and why
4 as each polypeptide chain has a haem group and each haem group carries oxygen
Does haemoglobin have a high or low affinity for oxygen and what does this mean
High so more oxygen can be transported around the body
In the lungs when oxygen joins the iron in haemoglobin what does it form
oxyhaemoglobin
What does this mean pO2 (imagine the 2 is small)
Partial pressure of oxygen
What is partial pressure of oxygen a measure of
Oxygen concentration
What is the relationship between partial pressure and affinity
The partial pressure of oxygen determines the affinity of haemoglobin for oxygen. If the partial pressure of oxygen is too high then the affinity of haemoglobin for oxygen is high so it binds
What do cardiac muscles control
the regular beating of the heart
What does myogenic mean
Myogenic means that the heart can make its own electrical signals to beat without needing outside help.
give a summary of the process of a heartbeat
- Sino atrial node (SAN) in the right atrium and it sends out regular waves of electrical conductivity to the atrial walls
-causes both atriums to contract at the same time - instead these waves are transferred from the SAN to the atrioventricular nodes (AVN) which is responsible for passing waves of electrical activity to the bundle of His
- bundle of His conducts waves of electrical activity to the purkyne tissue and this tissue carries the waves of electrical activity to the walls of the ventricles causing them to contract
What is the bundle of His
is a group of muscle fibres responsible for conducting the waves of electrical activity to the finer muscle fibres in the ventricle walls called purkyne fibres
what stops the waves of electrical conductivity from being passed from the atrium to the ventricles
-band of non conducting collogen tissue
What does an oxygen dissociation curve show
-the relationship between the percentage saturation of haemoglobin and the partital pressure of oxygen
What does the phrase “percentage saturation of haemoglobin” mean
-the proportion of haemoglobin molecules in the blood bound to oxygen, compared to the number of haemoglobin molecules able to carry oxygen
Why is the oxygen dissociation graph s shaped
-because when haemoglobin binds with the first O2 molecules its shape changes so it can bind to others easier
-but as the haemoglobin becomes saturated, it gets harder for more O2 molecules to join so the curve has a steep part in the middle where its easy for oxygen molecules to join
Does fetal or adult haemoglobin have a higher affinity for oxygen
fetal
How does the fetus get oxygen
-The fetus gets oxygen from its mothers blood across the placenta but by the time the mothers blood reaches the placenta, its oxygen saturation has decreased as some has been used by the mother so for it to get enough oxygen its haemoglobin affinity for O2 needs to be higher
What happens in the Bohr effect and carbon dioxide transport
cells respire and produce CO2 and this CO2diffuses out of the cell into the red blood cell and react with water(the catalyst is carbonic anhydrases) to form carbonic acid. This acid then dissociates into hydrogen carbonate ions(HCO3-) and H+ ions and the HCO3- diffuses out of the red blood cell in a process called the chloride shift when chlorine ions diffuse into the red blood cells
what is the structure of adult and fetal haemoglobin
-adult= 2 alpha chains and 2 beta chains
-fetus= 2 alpha chains and 2 gamma chains(for higher affinity)
Describe the Bohr effect
- When CO2 levels increases there is an increase in oxygen dissociation so the dissociation curve shifts to the right, showing O2 will dissociate from haemoglobin at lower pO2
