3.1.2 Transport in Animals Flashcards
summarise the different types of circulatory systems
Open system - have open ended blood vessels e.g amphibian circulatory systems in insects
closed- blood is in vessels and under pressure in fish and mammals
Relate the structure of the arteries to their function
Thick muscular walls to handle high pressures without tearing also contains collagen to allow it to be more elastic and have tensile strength.
elastic tissue allows recoil to prevent pressure surges
narrow lumen to maintain pressure
Relate the structure of veins to their function
Thin walls due to low pressure
Have valves to make sure blood doesn’t flow backwards
They have less muscular and elastic tissue as they dont have to control blood flow
Relate the structure of arterioles and venules to their function
Branch off arteries and veins in order to feed into smaller capillaries
They are both smaller then arteries and veins in order for a gradual change in pressure
Relate the structure of capillaries to their function
walls only one cell thick of an endothelium layer
very narrow - allows it to permeate tissues and so it can lie flat against the surface of the cell allowing for effective gas exchange
Many of them allows for a high surface area.
What is the blood of an insect called?
the blood of an insect is a haemolymph
half haemoglobin half lymph
Describe differences in the fish, amphibian and mammal transport systems
Fish - unidirectional, has only 1 atrium and 1 ventricle
gas exchange occurs in the gill filaments
Amphibians - Gas exchange in the lung and skin capillaries
deoxygenated blood and the oxygenated blood mix in the heart
Mammal- Has a septum to separate oxygenated and deoxygenated blood in the heart
Gas exchange occurred only in the lungs
what is water potential?
Measure of the tendency of water to move from place to another (so how easily will it diffuse)
What is tissue fluid?
It is plasma that gets pushed out through the fenestrations
contains oxygen, amino acids and other dissolved nutrients
Does not contain the plasma proteins
what types of pressure influence the movement of tissue fluid?
Hydrostatic pressure- higher at the arterial end (controlled by the heart contractions)
Oncotic pressure - is controlled by the capillaries water potential
How is tissue fluid formed ?
At the arterial end of the capillary the hydrostatic pressure is high
this pushes the tissue fluid out
This leaves a low water potential in the capillaries due to loss of liquid and only a high conc of plasma proteins
This increases the oncotic pressure
water moves into capillaries by osmosis
equlibrium reached so rest of plasma taken away by lymphatic drainage
how is tissue fluid different from blood and lymph
Tissue fluid is like blood but doesn’t have any red blood cells, platlets or plasma protiens
After tissue has surrounded cells it becomes lymph
so contains more waste products and less oxygen
describe the differences between arteries and arterioles
Arterioles
less elastin and less muscle so lower pulse
contain smooth muscle so can constrict and contract to control blood pressure
ARTERIES
arterial blood is under high pressure so contain a lot of elastin for elastic recoil
5 functions of blood
Transport waste and hormones
Involved in making tissue fluid
platelets for clotting
maintains body temperature
allows oxygen to reach cells.
why does the pressure in the arteries rise and fall?
Peaks are from the heart contracting (systole)
and the troughs are from the heart is relaxations (diastole)
The elastic recoil of the arteries prevent it from collapsing
Describe what happens during cardiac diastole
The heart is relaxed. Blood enters the atria increasing the pressure and pushing open the tricuspid and bicuspid valve. This allows blood to flow into the ventricles
This allows blood to travel into the ventricles
The ventricular pressure is still lower then aortic pressue so semi lunar valves are shut
Describe what happens during ventricular systole
The ventricles contract. The pressure increases so the AV valves shut to stop back flowback to the atria and the semi lunar valves enter
How do you calculate cardiac output?
cardiac output = heart rate x stroke volume
what does myogenic mean?
the hearts contraction is innated by its own muscle rather then a nerve impulse
Explain how the heart contracts
The sinoatrial node iniaties and spreads an excitation wave across both atria making them contract
(pressure increases which moves the blood into the ventricles)
And then the atrial ventricular valve has a time delay and
moves this down the bundle of his
This then moves into the purkyene fibers from the apex of the heart upwards
Why does the atrial ventricular node have a time delay?
Ensures the atria are completely empty of blood before ventricular systole
what is an electrocardiogram (ECG)
A graph showing the the amount of electrical activity within the heart during the cardiac cycle
what are the names of the types of abnormal activity
Tachycardia- fast heart beat
Bradycardia - slow heart beat
Fibrillation - irregular, fast heartbeat
ectopic - early or extra heartbeats `
What is meant by a double circulatory system
Blood flows into the heart twice in one heart beat
In PFO (a heart defect) shows a gap between the two arias
Suggest how PFO would lead to a migraine
A mix of oxygenated and deoxygenated blood reaches the brain leading to an oxygen debt which could cause pain in the form of a migrane
Describe the role of haemoglobin
present in red blood cells. Oxygen molecules bind to the haem group and are carried around the body , then released where they are needed in respiring tissues
How does partial pressure of oxygen impact the haemoglobins affinity for oxygen?
As partial pressure for oxygen increases, the affinity of haemoglobin also increases. When partial pressure of oxygen is low haemoglobin lets go.
Describe the Bohr effect
As partial pressure of of carbon dioxide increases this creates carbonic acid which is acidic
A lower pH changes the shape of the haemoglobin. So Hb affinitnity for oxygen now lowers
Explain the effect of carbonic anhydrase on the Bohr effect
Carbonic anhydrase is found present in red blood cells
converts carbon dioxide into carbonic acid which disassociates to form H+ ions
These combine with haemoglobin to form haemoglobinic acid which encourages the oxygen to leave the RBC
What is the purpose of HC03- in gas exchange
Produced along side the H+ ions,
70% of the carbon dioxide is formed in this way
In the lungs the ions are converted into Co2 and H20 which we breathe out
Describe the chloride shift
The intake of chloride ions after the HC03- ions leave in order to repolarise the red blood cell
Difference between foetal haemoglobin and adult haemoglobin
The blood in the placenta is carried at a low partial pressure of oxygen, therefore foetal haemoglobin will have a higher affinity to oxygen
Describe how the heart beat is inniated and how the contractions of the four chambers are co ordinated
The heart beat is myogenic
SA node is the pacemaker in the wall of the atria
Causes the wall of the atria to contract increasing atria pressure so blood goes into the ventricles
slight delay at the AV node to allow for atrial systole to be complete
this is continued through the bundle of his and the purkyene fibres through the apex to increase ventricle pressure and force blood through the aorta
How does smooth muscle in the trachea bronchus and bronchioles help its function?
This lining allows for less resistance, as the smooth muscle will relax during excercise this allows for a wider airway to let a larger volume of airflow through
explain the process of expiration
ribcage moves downwards and inwards;
external intercostal muscles relax;
diaphragm relaxes
Explain why the curve is so steep in oxygen dissociation curves
At low partial pressure there is little increase in oxygen concentration
However as the partial pressure increases it becomes easier for oxygen to bind to haemglobin
What does the QRS peak represent
ventricle systole
What does the P wave represent
Atrial systole
what does the T wave represent
ventricular diastole
Explain how water from tissue fluid is returned to the circulatory system
plasma proteins remain in the capillaries
this creates a water potential gradient between the venule end of the capillary and the tissue fluid
water moves into the capillary at the venule end by osmosis
water returns to the blood by the lymphatic system
