Transport in animals Flashcards
AVN (3)
Atrio ventricular node
Causes a slight delay to wait for atria to contract
Sends impulse down bundle of His connecting to purkyne fibres
P wave in ECG
Atrial systole
Contraction of atria
Atrial systole (3)
Pressure in ventricle is lower than atria
Blood build up in Atria causes contraction that increases pressure
Forces blood down atrioventricular valves
QRS wave in ECG
Ventricular systole
Ventricular systole (4)
Depolarisation of the parkyne fibres caused ventricular contraction
Pressure in ventricle higher that aorta and pulmonary artery
Atrioventricular valves shut
Forces blood up semi lunar valves
Diastole
Relaxation of ventricle and atria
Ventricles and atria fill with blood
T wave ECG
Diastole
Repolarisation of ventricles and atria
Myogenic contraction.
Heart beating without input from nervous system
Heart beats throughly electrical impulses from myocytes’ membrane
Bundle of His
Cardiac muscle cells that transmits electrical impulses from AV node to apex and
Purkyne fibres
Purkyne fibres (2)
Receive impulse from bundle of His
Cause cardiac cells to contract at apex and cause ventricular systole
SAN (3)
Sino-atrial node
Located at the right atrial wall
Causes depolarisation via impulse which causes atria to contract
Brief description of oxygenated blood pathway in heart (6)
- Comes through Pulmonary vein
- Left atrium
- Atrioventricular/ bicuspid valve
- Left ventricle
- Semilunar/ aortic valve
- Aorta/ Carotid arteries
Deoxygenated blood pathway in the heart (5)
- Superior/ Inferior vena cava
- Right Atrium
- Atrioventricular/ tricuspid valve
- Right ventricle
- Semilunar valve
Brief description of oxygenated blood pathway in heart (6)
- Comes through Pulmonary vein
- Left atrium
- Atrioventricular/ bicuspid valve
- Left ventricle
- Semilunar/ aortic valve
- Aorta/ Carotid arteries
Deoxygenated blood pathway in the heart (5)
- Superior/ Inferior vena cava
- Right Atrium
- Atrioventricular/ tricuspid valve
- Right ventricle
- Semilunar valve
Describe arteries (7)
- Carry blood at high pressure away from the heart
- Folded endothelium to ran able expansion under high pressure
- thickest layer of elastic fibre
- thickest layer of smooth muscle
- thickest layer of collagen to maintain strength under high pressure
- narrow lumen to maintain high pressure
- no valves
Describe veins (7)
- carries blood to heart under low pressure
- thinner smooth muscle later as exertion force is not high
- thinner elastic fibres as low pressure causes less recoil
- contains valves to prevent back flow
- Thin endothelium
- Thin layer of collagen as high pressure is not present
- Wide lumen: allows blood to flow easily.
Describe capillaries (5)
Allows exchange of materials within cells.
One cell thick endothelium which allows short distance for quick diffusion.
Small Lumen (10 micrometers) increase resistance which allows increases time for exchange of material.
Gaps in the walls allow many substances to pass through when materials are exchanges.
Very abundant: provides large surface area for diffusion.
Describe how tissue fluid is created at arterial end (3)
High hydrostatic pressure at arteriole end inside capillary
- outweighs the osmotic pressure forcing fluid inside capillary
- causes net flow of fluid out of capillary
Describe tissue fluid movement at venous end (4)
- osmotic pressure is still constant
- hydrostatic pressure decreased as fluid left at arterial end
- osmotic pressure into capillary outweighs hydrostatic pressure out of capillary
- causes net movement of fluid into capillaries
Describe pathway of electrical impulses in the heart (4)
- SAN depolarises to release impulse that spreads across both atria
- band of tissue prevents conduction into ventricle
- AVN waits for atria to contract before sending impulse down bundle of His
- impulse travels to Purkyne fibres which cause ventricular contraction upwards from the apex
Tachycardia (3)
- rapid heart beat over 100bpm
- occurs during exercise
- has evenly spaced QRS complex
Bradycardia (2)
- very low heart rather; below 60 Bpm
- common amongst for athletes
Ectopic heartbeat (3)
- heart beat out of rhythm
- irregular QRS complex
- long intervals before P wave
Atrial fibrillation (3)
- extremely rapid impulses up to 400bpm
- abnormal heart rhythm
- impulses not passed to ventricles
Describe the pathway of CO2 in erythrocytes (4)
- diffuses and combines with H2O to force carbonic acid
- carbonic acid dissociates into H+ and HCO3- ions
- HCO3- ions leave rbc whilst Cl- comes into to maintain charge in ‘chloride shift’
- H+ reacts with Hb to form haemoglobonic acid to maintain pH
How is oxygen released from rbc
Oxyhemoglobin dissociates to form 4 O2 molecules and Hb
Affinity
Attractive force between substances or particles
Eg Haemoglobin and O2
Role of carbonic anhydrase in transport of CO2
Catalysed the reaction between CO2 and H2O
To from carbonic acid
How is O2 released from erythrocytes
Oxyhemoglobin dissociates into;
Haemoglobin
4 O2 molecules
Describe Bohr effect (5)
- Occurs in increased H+ ions, CO2 and temperature
- When partial pressure of CO2 is high, partial pressure of O2 is low
- Causes reduction in Hb affinity to O2 and increases Hb affinity to CO2
- Causes O2 to be unloaded whilst CO2 is loaded onto haemoglobin
- This is shown by the right shift in the O2 dissociation curve
Explain fetal haemoglobin shift (4)
- Fetal haemoglobin has greater affinity to oxygen than adult Hb
- The mother’s bloodstream already has high CO2 but the fetus requires O2.
- Fetal haemoglobin’s higher affinity to O2 allows the fetus to draw O2 from the mother’s blood.
- This is shown by the left shift in the oxygen dissociation curve
Explain the curve of oxygen dissociation curve (4)
The overall shape is an ‘s’ curve:
- The small slope at the start: Low p(O2) so haemoglobin has low affinity to O2.
- Steep increase in Hb concentration:
The first O2 molecule binding causes a ‘conformational change’ in the shape of Hb. The allows Hb affinity to O2 to increase allowing 2nd and third O2 molecules to bind. - Plateaus:
At very high O2 concentrations, it is difficult for the final O2 molecule to bind.
Haemolymph (4)
- Transport fluid in insects
- Not contained in vessels
- Does not contain H2O, CO2
- Transport food, waste products, immune cells
What is formed when haemoglobin reacts with carbon dioxide
Carbaminohaemoglobin
What does an increase in temperature and H+ ions cause Bohr shift (2)
- H+ ions bind to Hb. When affinity of Hb to O2 is decreased, Hb can bind with H+
- Increased temp increase rate of carbonic acid reaction as more kinetic energy in carbonic anhydrase causes more collision- quicker rate of reaction
Need for specialised transport system in animals? (5)
- High metabolic demands (food, waste, oxygen) in large multicellular animals. DIffusion alone cannot cover demand.
- Small SA:V ratio in large organisms. Greater distance for diffusion and less surface to remove and absorb substances.
- Molecules created in one section but needed in another. Eg hormones and enzymes.
- Waste products removed from each cell to be transported into excretory organs
- Food digested in one organ system and transported to every cell.
Opened circulatory system. (4)
- Transport medium not contained in many vessels.
- Medium pumped from heart straight to haemocoel
- Medium comes into straight contact with tissues and cells.
- common in insects and small organisms.
Single circulatory system.
Blood goes through the heart once in ONE circulation.
Double circulatory system.
Blood goes through the heart TWICE in ONE circulation.
Closed circulatory system. (3)
- Blood is enclosed in blood vessels
- Heart pumps blood under high pressure and blood returns straight to the heart.
- Substances leave and enter blood via diffusion into and out of blood vessel walls.
Similarities between open and closed circulatory systems.
- Contain liquid transport medium.
- Contain pumping mechanism to move medium.
- Contain vessels to transport medium.
Why do land predators have double circulatory system? (5)
- Move in fast bursts
- Grow to be quite large and therefore have high metabolic demands
- Body needs to be supported against gravity.
- Double system allows blood to be oxygenated at lungs before being transported to the body
- More efficient as greater amount of oxygen can be supplied to tissues and more CO2 out.
Why do aquatic predators have a single circulatory system? (5)
- Does not need to be as efficient as bony fish contain operculum which allow continuous flow of water over gills
- Countercurrent also allows efficient oxygen uptake.
- They are supported by water, therefore less energy in supporting themselves.
- Poikilothermic
Overall demand for tissue is not as high a land animals therefore single is adequate enough.
Platelets (3)
Fragments of larger cells called ‘megakaryocytes’
Component of blood involved in blood clotting mechanism
Prevents excessive hemorrhage
Lymph (3)
Modified tissue fluid;
More CO2, waste and fatty acid
Less oxygen and food molecules
Tissue fluid
Contains plasma contains apart from proteins.
What effect does increased permeability have on surrounding tissues (5)
- Inflammation/ swelling of tissue
- more pressure inside the tissues
- increase in tissue fluid
- more white blood cells can enter tissue
- larger molecules can enter the tissues
Why does the left ventricle have the thickest wall (4)
- Blood has the greatest distance to travel
- Pumps blood to the rest of the body
- More force is required to generate a higher pressure
- The blood also has greater resistance to go through
Describe the pressure changes in a cardiac cycle.
- At atrial systole: pressure in atria is greater than the ventricles. Causes blood to move to the ventricles
- Ventricular systole; pressure in ventricles greater than aorta, blood into aorta
Arterioles (3)
Connect arteries with capillaries.
Contains sphincters which contract and relax. When contracted, it prevents blood flow to the capillary bed (Vasoconstriction).
Vasodilation occurs when sphincters expand the venules, allowing more blood flow to the capillary bed..
What adaptations does the body have to overcome blood flowing against gravity? (3)
Valves in veins: prevents backflow of blood as it only allows blood to travel in one direction.
Veins ruin between active muscles: This squeezes blood upwards when the muscles contract.
Breathing movements: This acts as a pump due to the pressure changes and squeezing which pushes blood towards the heart.
Differences between blood and tissue fluid? (5)
Blood: Contains large plasma proteins.
Tissue fluid: Does not contain large plasma proteins.
Blood: Contains red blood cells.
Tissue fluid: Does not contain red blood cells.
Blood: Contains platelets.
Tissue fluid: Does not contain platelets.
Blood: Contained in blood vessels.
Tissue fluid: Not contained into vessels.
Blood: Under relatively higher pressure compared to tissue fluid.
Explain adaptations in insects that allow an increased surface area for gaseous exchange.
Insects contain an abundant amount of tracheoles that branch off from the tracheae.
Each cell is connected to a tracheole. This allows quick diffusion of O2 and CO2.
Explain adaptations in insects that allow concentration gradients to be maintained for gaseous exchange.
Respiring cells at the end of the tracheoles allows steep concentration gradient to be made:
High O2 at the mouth —> low O2 at respiring tissue.
Low CO2 at the mouth
Explain how the fish have adaptations that allow a large surface area for efficient gaseous change.
Gill filaments with lamellae are very abundant.
Greater surface area overcomes problem of small surface area to volume ratio.
Allows quick rate of diffusion.
What adaptations in fish allow a concentration gradient to be maintained?
Countercurrent flow:
Blood flows in the opposite direction to water. The allows steep concentration gradient of oxygen to be maintained.
Ventilation allows continuous O2 going in and CO2 going out.
Tunica media
The layer in between the tunica externa and tunica intimia, located in veins and arteries.
Composed of smooth muscle and elastic tissue.
Tunica intima
The innermost layer in veins and arteries.
Composed of one layer of endothelium tissue and elastic tissue.
Tunica adventitia
Outermost layer in veins and arteries, which surrounds the tunica media.
Mainly composed of collagen.
