Transport in Animals, 3.2 Flashcards
What do we use as a transport medium in the body?
Blood
How is blood pumped through vessels?
Muscle contraction of the heart
Why does blood only flow in one direction?
Due to valves
What is a single circulatory system?
Flows through the heart once. Heart - gills - body. Is a slow delivery system
What organism uses a single circulatory and why?
Fish. Don’t need to maintain their body temperature - less energy.
What is a double circulatory system?
Two circuits. The pulmonary and the systematic. Goes through the heart twice. Heart - body - heart - lungs.
What is the pulmonary circulation system?
Carries blood to the lungs - pick up oxygen
What is the systematic circulation system?
Carries and nutrients to the body tissues.
Does systematic or pulmonary have a higher pressure? Why?
Systematic. Blood has further to travel to all parts of the body.
What are the main features of an open circulatory system?
Blood flows through body cavity - carries nutrients. Oxygen delivered directly though tiny holes. Low blood pressure. Slow blood flow.
Give an example of an organism that uses an open circulatory system?
Insect
What are the main features of a closed circulatory system?
Blood flows through vessels. Heart pumps blood. Tissue fluid bathes cells. Higher pressure - quicker.
Give an example of an organism that has a closed circulatory system.
Humans
In which direction do arteries carry blood?
Away from the heart
What are the key features of an artery?
Thick walls - withstand high pressure. Small lumen - maintains pressure. Inner wall folded so lumen can expand.
What muscle/tissue do the 3 different layers in an artery contain?
Inner - elastic. Middle - smooth muscle. Outer - collagen, elastic.
What is elastic recoil?
Prevents blood moving in a stop start fashion
What is the role of an arteriole? And what are its main features?
Distribute blood from artery to capillary. Contain smooth muscle - can contract.
Which direction do veins carry blood?
Towards the heart (in).
What are the main features of a vein?
Low pressure - walls don’t need to be thick. Large lumen.
What muscle/tissues do veins contain?
Collagen. Smooth muscle. Elastic tissue. Valves - prevent blood flowing the wrong way.
What is the role of a venule?
Blood from capillary to vein.
What features make a capillary good from exchanging fluid?
Thin walls. Lumen is narrow. Walls are one cell thick. Walls are ‘leaky’.
What is tissue fluid the result of?
Hydrostatic pressure. Osmosis. Plasma leaving.
What is the role of tissue fluid?
Bathes cells and tissues so gas exchange an take place
How is tissue fluid formed?
- Heart contracts - exerts hydrostatic pressure. Fluids push against capillary walls.
- High pressure at arterial end - fluid moves out of capillary
- Leaves through tiny gaps - dissolve gases and nutrients
- Larger molecules (proteins) do not
How do substances from tissue fluid return to the blood?
- Hydrostatic pressure at venule end much lower
- High solute potential so fluid will be drawn back in via osmosis
Can also be drained through th lymphatic system.
How does the lymphatic system work?
- Drains excess tissue fluid
- Is now called lymph
- Returns to blood system near the heart
- Lymph contains lymphocytes which are made in lymph nodes
What does myogenic mean?
Heart initiates its own contractions
What are the two main pumping chambers called?
Ventricles
What are the two thin walled chambers called?
Atria
What is the role of the coronary artery?
Supplies oxygenated blood to the heart
Which vessel delivers deoxygenated blood to the atria?
Vena cava - to right atrium
Which vessel delivers oxygenated blood to the atria?
Pulmonary vein - left atrium
What is the name for the valves between the atria and the ventricles?
Atrio-ventricular valves.
What does valves have attached to them to stop them turning inside out?
Tendinous cords.
Which vessel carries blood from the ventricle to the lungs?
Pulmonary artery - right ventricle
Which vessel carries blood from the ventricle to the body?
Aorta - left ventricle
How does high pressure effect the blood?
It is pushed further
Where are semi-lunar valves found? What is their role?
Base of major arteries. Prevent blood returning to the heart when ventricles relax.
Describe the features of the atria
Low pressure. Thin walls. Doesn’t need to move blood far.
Describe the main features of the right ventricle..
Thicker walls. Pump blood to the lungs - not very far. Deoxygenated blood.
Describe the features of the left ventricle.
Very thick walls. Pumped all over the body - need high pressure.
Adaptations of the cardiac muscle
Fibres branch forming cross bridges. Ensure muscle an squeeze. Many mitochondria.
What happens during diastole?
Muscular walls of the chambers relax. Elastic recoil. Chambers increase in volume. Blood flows in.
What happens during atrial systole?
Right and left atria contract. Small pressure increase created. Pushes blood into ventricles - stretches their walls.
What happens during ventricular systole?
Both right and left ventricles pump together. Contraction starts at the base. Blood pushed up tot he arteries.
How do atrio-ventricular valves work?
- Blood pressure in ventricles drops
- Valves open and blood flows through
- Pressure increases
- Valves close when atria relax and ventricles are full
- Blood in valve pockets keeps them closed
How do semi-lunar valves work?
- Before contraction higher pressure in arteries so valves are closed
- Pressure rises in ventricles - valves open
- Blood is forced out
- Heart relaxes and pressure drops
- Blood flows back towards ventricles - valves kept closed by blood in valve pockets
What does SAN stand for?
Sino-atrial node
What is the role of the SAN?
Generates electric activity. - spreads throughout atria walls and causes muscles to contract (atrial systole)
What happens at the base of the atria?
Tissue is unable to conduct the SAN wave so it is picked up by the AVN
What does AVN stand for?
Atrio-ventricular node
How does the AVN causes heart muscles to contract?
Short delay so atria finishes contracting. Wave is carried by Purkyne tissue - runs down intervecular septum.
Where does the wave of excitation spread from after being produced by AVN?
Spreads from the apex of the ventricles. Causes muscle to contract upwards. Pushes blood up.
What do electrocardiograms do?
Monitor hear activity.
How do electrocardiograms work?
Places sensors around the body - connect to a monitor. Measures the electrical signals.
What is normal heart rate called?
Sinus rhythm
What is slow heart rate called?
Bradycardia
What is fast heart rate called?
Tachycardia
What is irregular heart rate called?
Ectopic
How is oxygen transported/
In red blood cells - haemoglobin has the ability to take up oxygen.
How many haem groups does haemoglobin have?
4
What does each haem group contain?
Iron ion
What does haemoglobin and oxygen form?
Oxyhaemoglobin
What is the name when haemoglobin releases oxygen?
Dissociation
What dos the ability of haemoglobin to associate/dissociate depend on?
The concentration of oxygen in the surrounding tissue.
What is partial pressure?
The relative pressure to measure oxygen concentration
When will haemoglobin release oxygen?
When there is low oxygen
What is an S curve?
Created by haemoglobin dissociation.
When dos oxygen associate?
At high oxygen tension
What happens to the S curve when the haemoglobin gains one cell? What happens to the affinity for oxygen?
Makes it easier for oxygen to associate. Causes a steep increase..
Where is the highest point of the S curve?
At the lungs
Where will the fetal haemoglobin graph lie in compared to the adult haemoglobin graph?
To the left
Fetal haemoglobin has a high affinity for oxygen, what does this mean?
Associates oxygen at low concentrations
Why does fetal haemoglobin have such a high affinity for oxygen?
Needs as much oxygen after the mother uses the oxygen. There would be low oxygen tension.
Where is myoglobin found?
In muscle cells - there is high oxygen demand
Why does oxygen dissociate at lower concentrations?
Prevents anaerobic respiration. Loads at low partial pressures.
Why is the transport of carbon dioxide important?
CO2 is released from respiring tissues. Needs to be removed and transported to the lungs.
Name the 3 ways CO2 is transported?
- 5% dissolved in plasma
- 10% combined with haemoglobin
- 85% transported in the form of hydrogen carbonate ions
What is the equation for the formation of hydrogencarbonate ions?
CO2 + H2O — H2CO3 — H+ +HCO3-
How are hydrogencarbonate ions formed?
- CO2 in plasma diffuses into RBCs
- Combines with water to form carbonic acid
- Dissociates to H+ and HCO3-
- Hydrogencarbonate ions diffuse out of the cell
- Charge is maintained by chloride ions
What happens to the H+ ions?
- Become acidic if they build up
- Associate with haemoglobin - produce haemoglobinic acid
- Acts as a buffer
When is haemoglobin free to take up H+?
When it has released oxygen
Describe the Bohr effect?
- Carbonic acid — H+
- Affects the pH of cytoplasm
- PH changes tertiary structure of protein
- Can’t hold as much oxygen
- Results in more oxygen being released where more carbon dioxide is produced
Why would a weak heartbeat result in fatigue?
- Low pressure, slower blood flow
- Less oxygen reaching respiring cells
- Less glucose reaching respiring cells
- Less ATP produces
- Build up if CO2