F211 Transport In Animals Flashcards
Veins
Function
Transport deoxygenated blood back to the heart at low pressure
Arteries
Function
Transport oxygenated blood away from the heart at high pressure
Capillaries
Function
Transport both oxygenated and deoxygenated blood past cells to allow for the exchange of materials
Arteries
Lumen Size
Relatively small to maintain blood pressure
Veins
Lumen Size
Relatively large to ease the flow of blood
Capillaries
Lumen Size
Very narrow to ensure that erythrocytes are squeezed helping them to give up their oxygen and reducing the distance for diffusion
Arteries
Endothelium
Folded but can unfold when the artery stretches to reduce friction with the blood
Veins
Endothelium
Smooth to reduce friction
Capillaries
Endothelium
Smooth to reduce friction
Arteries
Muscular Tissue
Thick layer stretches to allow the blood vessel to with stand high blood pressure
Veins
Muscular Tissue
Thin layer as they don’t have to withstand high blood pressure
Capillaries
Muscular Tissue
Not present
Arteries
Elastic Fibres
Thick layer recoils to constrict the lumen size and maintain high blood pressure
Veins
Elastic Fibre
Thin layer as they don’t need to maintain pressure
Capillaries
Elastic Fibre
Not present
Arteries
Valves
Not present
Veins
Valves
Prevent the blood from flowing backwards the wrong way because it is at low pressure
Capillaries
Valves
Not present
Arteries
Collagen
Thick layer to reinforce the wall
Veins
Collagen
Fibrous proteins or strength
Capillaries
Collagen
Not present
Myogenic Heart
The heart produces its own impulses so controls its own beating
Open Circulatory System
Simple heart pumps blood into a big open cavity around the organs inside the organism
Substances in the blood diffuse into cells
Blood is sucked back into the heart through small valved openings when the heart relaxes
There are no blood vessels
Open Circulatory System
Disadvantages
Very inefficient
Takes a long time
Single Closed Circulatory System
Blood flows through the heart once in each circulation of the body
Single Closed Circulatory System
Fish
Atrium receives blood from the body
Ventricle pumps blood to the gills
Gas Exchange
Blood pumped to body
Single Closed Circulatory System
Advantages
Blood travels faster and at higher pressure than an open circulatory system
Substances transported more efficiently so the organism can be bigger and more active
Single Closed Circulatory System
Limitations
Blood pressure drops between gas exchange and body
Double Closed Circulatory System
A transport system in which blood travels twice through the heart for each complete circulation of the body
Double Closed Circulatory System
Mammals
Right atrium receives deoxygenated blood from the body
Right ventricle pumps deoxygenated blood to the lungs
Left atrium receives oxygenated blood from the lungs
Left ventricle pumps oxygenated blood to the body
Double Closed Circulatory System
Advantages
Blood pressure is increased after gas exchange so blood is pumped to the body at a higher pressure The systemic (body) circulation can carry blood at higher pressure than the pulmonary circulation
Double Closed Circulatory System
Limitations
Blood pressure cannot be high in the pulmonary circulation as delicate lung capillaries as they may be damaged
Large Animal Transport Systems
Size
Once an animal has a few layers of cells respiration by diffusion is no longer effective
Oxygen is used up by the outer cells
A transport system is required
Large Animal Transport Systems
Surface Area : Volume Ratio
Large animals have a small surface area to volume ratio
Their surface area is too small to supply all the oxygen and nutrients they need by diffusion
They require a transport system
Large Animal Transport Systems
Activity
If an animal is very active then it’s cells need a good supply of oxygen to respire and produce energy
It needs an efficient transport system
The Mammalian Heart
Body Vena Cava Right Atrium Open Right Atrioventricular Valve Right Ventricle Close AV Valve Open Semi Lunar Valve Pulmonary Artery Lungs Pulmonary Vein Left Atrium Left Atrioventricular Valve Left Ventricle Close AV Valve Open Semi Lunar Valve Aorta Body
Heart Action
Sinoatrial Node produces electrical impulse Impulse travels over atria causing atrial systole Impulse reaches Atrioventricular node Time delay Impulse travels down bundle of his Impulse travels along purkinje fibres Ventricular systole Diastole
Heart Action
Non Conductive Tissue
Between the atria and ventricles
Prevents impulse from travelling straight across the ventricles from the atria
Instead the impulse travels up the sides of the ventricles from the apex of the heart pushing blood upwards through the semi lunar valves
Heart Action
Why is there a time delay?
To allow time for the atria to empty and the ventricles to fill
Purkinje Fibres
Specially adapted muscles fibres that conduct a wave of excitation from the atrioventricular node down the septum to the ventricles
Sinoatrial Node
The heart’s pacemaker
Small patch of tissue
Sends out electrical impulses at regular intervals to initiate contractions
Electrocardiogram
Purpose
Monitors the electrical activity of the heart
Electrocardiogram
P Wave
Atrial systole
Electrocardiogram
PR Interval
Time delay at atrioventricular node
Electrocardiogram
QRS Complex
Ventricular systole
Electrocardiogram
T Wave
Diastole
Electrocardiogram
Elevated ST Segment
Indicates a heart attack
Electrocardiogram
Small P Wave
Atrial fibrillation - uncontrolled contraction
Electrocardiogram
Deep S Wave
Ventricular hypertrophy- increased muscle thickness to overcome high blood pressure due to a blockage in a blood vessel
Blood / Hydrostatic Pressure
Measure of hydrostatic force exerted on the walls of a blood vessel by the blood
Blood Pressure
Top Number
Systole
Maximum blood pressure when heart contracts
Blood Pressure
Bottom Number
Diastole
Heart at rest
Low Blood Pressure
Inefficient
High Blood Pressure
Damage to blood vessel walls
Edema- swelling due to retention of tissue fluid in cells
Formation of Tissue Fluid
Low hydrostatic pressures from tissue fluid
Little movement of water into blood by osmosis
Blood enter capillaries at high pressure
Plasma is forced out of the blood through fenestrations in the capillary walls
Movement of Tissue Fluid Back into Blood
Low blood pressure at the end of the capillaries
High hydrostatic pressure from tissue fluid
Water moves back into blood by osmosis
Tissue Fluid and Lymph
20% of tissue fluid drains into blind ended lymph capillaries
It flows in the lymph vessels and returns to the blood via the thoracic duct in the neck
Blood
Hydrostatic Pressure
High
Tissue Fluid
Hydrostatic Pressure
Low
Lymph
Hydrostatic Pressure
Low
Blood
Large Proteins
Yes
Tissue Fluid
Large Proteins
No
Lymph
Large Proteins
No
Blood
Neutrophils
Yes
Tissue Fluid
Neutrophils
Yes
Lymph
Neutrophils
Yes
Bloods
Erythrocytes
Yes
Tissue Fluid
Erythrocytes
No
Lymph
Erythrocytes
No
Blood
Oxygen
More
Tissue Fluid
Oxygen
Less
Lymph
Oxygen
Less
Blood
Carbon Dioxide
Less
Tissue Fluid
Carbon Dioxide
More
Lymph
Carbon Dioxide
More
Haemoglobin
4 globular proteins
1 iron ion - prosthetic group
Each molecule bonds to 4 oxygen molecules
Dark red
Allows erythrocytes to carry respiratory gases
High affinity for oxygen
Oxyhemoglobin
Bright Red
Haemoglobin
Percentage Saturation and Partial Pressure
It is difficult for the first oxygen molecule to bind because the haem group is at the centre
When it is attached it changes the shape of the haemoglobin molecule making it easier for the second and third molecules to bind
It is very difficult for the fourth oxygen molecule to bind so the graph plateaus before 100%
Diffusion of Oxygen
Alveoli to Erythrocyte
Oxygen diffuses from high partial pressure in the lungs to a lower partial pressure in the blood plasma
Then diffuses from low partial pressure in the plasma to a lower partial pressure in the erythrocytes
Diffusion of Oxygen
Erythrocytes to Respiring Tissue
Oxygen dissociated from oxyhemoglobin at respiring tissue into the plasma
Then diffuses into the respiring cells where the partial pressure of oxygen is very low
Fetal and Maternal Haemoglobin
Feral haemoglobin has a higher affinity for oxygen so that oxygen moves from the maternal blood to the fatal blood at the placenta
Feral and maternal blood must be kept separate or an immune response will be triggered
Higher oxygen affinity allows foetal haemoglobin to become saturated with oxygen at a lower partial pressure of oxygen
Transport of Carbon Dioxide
Dissolved in Plasma - 5%
Associated with haemoglobin, carbamionhaemoglobin - 10%
As hydrogen carbonate ions - 85%
The Bohr Effect
Definition
The effect of carbon dioxide on the affinity of haemoglobin for oxygen
The Bohr Effect
Stages
Carbon dioxide diffuses into erythrocyte
Combined with water by enzyme carbonic anhydrase
Forms carbonic acid
Carbonic acid dissociates in to hydrogen and hydrogen carbonate
Negative hydrogen carbonate ion diffuses into plasma
Chloride ions shift into erythrocyte to equalise charge
Hydrogen ion increases acidity
Oxyhemoglobin dissociates under influence of hydrogen ions
Oxygen is released into the blood
Haemoglobin neutralises hydrogen forming haemoglobinic acid
