3.2 Transport in animals Flashcards
Why do bigger animals need specialised transport systems
Distances between cells and outside get bigger
Higher metabolic demands
Smaller surface area to volume ratio
molecules may be produced in one place, but needed in another
Waste products need to be removed
What features are in circulatory systems/mass transport systems
Liquid transport medium (blood)
Vessels to transport medium
Pumping mechanism to move fluid
Open circulatory system:
Very few vessels, pumped from heart into body cavity, transport medium, cells
What is insect blood called, what does it do?
Haemolymph, carries food and nitrogenous waste products.
How is an insect’s body cavity split?
Membrane, heart extends along length of the thorax and abdomen.
Closed circulatory system:
Blood is enclosed in blood vessels, and does not come in contact with cells. Heart pumps blood around the body, substances enter and leave blood through diffusion through walls of blood vessels
Single closed circulatory systems: Example
Blood flows through heart only once for each complete circulation of the body Fish
What makes fish exchange surfaces effecient
Counter current gaseous exchange
Double closed circulatory system: example
Blood is pumped from the heart, to the lungs, returns to the heart, travels all around to body, and returns back to the heart
Birds and most mammals
What does a double closed circulatory system help with
High pressure and fast flow of blood
What are elastic fibres and function
Composed of elastin, stretch and recoil, provides vessel walls with flexibility
What are smooth muscle and function
Contracts and relaxes
Changes size of lumen
What is collagen and function
Provides structural support to maintain shape and volume of the vessel
Arteries:
Most carry oxygenated blood,
away from the heart other then pulmonary artery and umbilical artery which carries deoxygenated blood.
High pressure
Artery structure:
Lumen
Endothelium
Elastic Layer
Muscle Layer
Tough outer layer (collagen)
What is the lumen
Where blood cells are
What is the purpose of elastic fibres in arteries
Recoil and return to original length in between contractions, evening out surges of blood
What is the purpose of collagen in arteries
Allows the arteries to stretch within a limit during surges
What is the purpose of smooth muscle in arteries
constrict and dilate to control the flow of blood
What is vasconstriction
Smooth muscle in arteries contract, constricting the vessel
What is vascodilation
Smooth muscle in arteries relaxes, dilating the vessel
What is an aneurysm
Bulge or weakness in a blood vessel - can burst and be fatal if untreated
What is an arteriole and venules
smaller blood vessels that attach to capillaries
What is a capillary
One cell thick, one red blood cell wide blood vessels, allow for exchange of molecules
Blood enters the capillaries____ and leaves____. Two exceptions to this is___ and ____
Enters Oxygenated, Leaves deoxygenated.
Lungs and placenta
Capillaries adaptations:
Large surface area to volume ratio.
Slower movement of blood
Single celled walls
Veins:
Most carry deoxygenated blood
Away from heart, apart from lungs and heart.
Vein Structure:
Lumen
Endothelium
Elastic Layer
Muscle Layer
Tough outer layer (collagen)
Blood flow path:
Artery, arterioles, capillaries, venules, veins, capillaries
Do veins have a pulse?
No - surges are lost through capillaries, this means they are very low pressure
How does the blood in veins flow against gravity
Muscles contract and squeeze the vein - forcing the blood to the heart
How do breathing movements impact on veins
Act as a pump - pressure changes and squeezing actions move blood in veins in chests and abdomen towards the heart
How do valves in the veins work
One way valves
Blood flows in correct direction = valves open
Blood flows backwards = valves close
Importance of valves in veins:
Prevents backflow of blood - blood must flow against gravity
What does blood consist of
Plasma, erythrocytes, platelets, lymphocytes/leucocytes
What is plasma
Component of blood that carries dissolved glucose, amino acids, mineral ions, hormones, plasma proteins, fibrinogen, and globulins.
What is the function of plasma protein albumin
maintaining osmotic potential of blood
What is the function of fibrinogen in the plasma
blood clotting
What is the function of globulins in the plasma
transport and the immune system
What else does plasma transport
Red blood cells, different types of white blood cells, platelets
What is the function of red blood cells
carry oxygen to cells in haemoglobin
What are platelets
Fragments of large cells found in red bone marrow, involved in clotting blood
What are the functions of blood
Transport of oxygen and carbon dioxide
digested foods from small intestine
Nitrogenous waste products from cells to excretory organs
Hormones
food molecules from storage
Platelets to damaged areas
Cells and antibodies involved in immune response
What is tissue fluid
Fluid squeezed out of capillaries, filling the space between cells, allowing for diffusion
What is the use of tissue fluid
Helps with gas exchange.
What is tissue fluid made from
Plasma, without red blood cells and plasma proteins
Explain the formation of tissue fluid
Hydrostatic pressure is higher then the oncotic pressure at the arterial end is of the capillary forces fluid out of the capillaries.
Explain the removal of tissue fluid
Oncotic pressure is higher then the hydrostatic pressure at the venous end of the capillary, forcing fluid into the capillaries.
What is oncotic pressure
Tendency for water to move into the blood via osmosis
What is hydrostatic pressure
pressure from blood surges, forcing fluid out of the capillaries.
What is lymph
tissue fluid that does not return to the capillaries, drains into lymph capillaries
What is lymph composed of
Similar to tissue fluid, but with less oxygen and fewer nutrients. Contains fatty acids
What are lymph nodes
Along lymph vessels. Lymphocytes build here and produce antibodies.
Intercept bacteria and other debris, which are ingested by phagocytes.
What are enlarged lymph nodes a sign of
Body is fighting off an invading pathogen
What happens to lymph after it travels through lymph vessels
returns to blood plasma
What are erythrocytes
red blood cells
How are erythrocytes adapted to their funtion
Biconcave shape - higher surface area for gas exchange, and allowing them to pass through capillaries.
No nuclei - maximises space for haemoglobin
What do erythrocytes contain that is needed for their function
Haemoglobin - globular protein made from four peptide chains, with an iron containing haem prosthetic group
How many molecules of oxygen can bind to one haemoglobin molecules.
What is the reaction for this
Four.
Haemoglobin + Oxygen -><- oxyhaemoglobin
Hb+4O2 -><- Hb(O2)4
How does oxygen move into erythrocytes
erythrocytes enter capillaries in lungs, this has a steep concentration gradient. Oxygen moves into erythrocytes and bind to haemoglobin.
How is haemoglobin adapted for efficient oxygen exchange? - What is positive cooperativity
When one oxygen molecule binds to haem group, then the molecule changes shape. making it easier for the next molecule to bind
When oxygen is released by haemoglobin, the molecule changes shape, becoming easier to remove.
How does oxygen move out of erythrocytes
Concentrating of oxygen in body cells are lower then in the erythrocytes, oxygen moves down concentration gradient, oxygen is released by haemoglobin.
What do oxygen dissociation curve shows
show the affinity of haemoglobin to oxygen
Why is not all oxygen (around 25%) leaving haemoglobin important
Acts as a reserve for then demands of the body increase rapidly
What is the effect of carbon dioxide on Oxygen dissociation curves
Bohr shift - oxygen dissociation curve for haemoglobin moves to the right
haemoglobin gives up oxygen easier
Why is Bohr shift important
Active tissues need haemoglobin to give up oxygen easier
In lungs, oxygen binds to haemoglobin easier, when carbon dioxide in the air is low
How does Foetal haemoglobin differ from adult haemoglobin
Foetal haemoglobin has a higher affinity for oxygen then adult.
Why is foetal haemoglobin having a higher affinity for oxygen important
oxygenated blood from mother runs close to foetal, deoxygenated blood in placenta. Removal of oxygen from maternal blood
Compare adult and foetal haemoglobin on an oxygen dissociation curve
foetal haemoglobin is shifted to the left, meaning at the same partial pressure of oxygen, foetal haemoglobin will have higher percentage saturation
How is carbon dioxide transported
Dissolved in Plasma, carbonic haemoglobin, hydrogen carbonate ions
Carbon dioxide reacts with water to form carbonic acid, Carbonic acid then dissociated to form hydrogen ions and hydrogen carbonate ions
CO2 + H2O -><- H2CO3 -><- H+ HCO3-
Carbonic anhydrase catalyses what reversible reaction
Carbon dioxide and water to form carbonic acid
What does carbonic acid do
Dissociates to form hydrogen carbonate ions and hydrogen ions
What happens to negatively charged hydrogen carbonate ions
move out of erythrocytes into the plasma via diffusion
What happens after negatively charged hydrogen carbonate ions diffuse out of erythrocytes
Negatively charged chloride ions move into erythrocytes (chloride shifts)
What does removal of carbon dioxide, converting it to hydrogen carbonate ions do
Maintain a steep concentration gradient for carbon dioxide to diffuse into erythrocytes
What happens when deoxygenated blood reaches the lungs
Carbonic anhydrase catalyses the reverse reaction, breaking down carbonic acid into carbon dioxide and water. Hydrogen carbonate ions diffuse back into erythrocytes, react with hydrogen ions to form carbonic acid, releasing carbon dioxide, which diffuses out of the erythrocytes into the lungs, chloride ions diffuse out of red blood cells.
At lungs: Carbonic anhydrase catalyses the reverse reaction….
breaking down carbonic acid into carbon dioxide and water
At lungs: Hydrogen carbonate ions diffuse back into erythrocytes,
react with hydrogen ions to form carbonic acid, releasing carbon dioxide. Chloride ions diffuse out, because electrical balance has been maintained.
How is haemoglobinic acid formed? Why?
Acts as a buffer prevents pH change by accepting free hydrogen ions, forming haemoglobinic acid
What does the human heart consist of
Cardiac muscles, two pumps
What is the advantage of cardiac muscle
Does not get fatigued, need oxygen supply - supplied by coronary arteries
Outline the flow of deoxygenated blood in the heart
Flows into the right side of the heart (superior (from head) and inferior vena cava (from body)), into the right atrium, across the tricuspid (atrioventricular valve), into right ventricle, through semi-lunar valve, then out of pulmonary arteries and too lungs
Outline the flow of oxygenated blood in the heart
Flows into left side of the heart (Pulmonary veins), into left atrium, pressure builds in atrium, blood moves through open bicuspid (atrioventricular valve), into left ventricle, through, semilunar valve, then into aorta, and out to the body.
Outline the flow of blood in the heart
Blood enters the atria, pressure builds, atrioventricular valves open, blood flows into the ventricles, When blood fills the atria and ventricles, atria contract, forcing the blood into the ventricles, atrioventricular valve closes, ventricles contract, forcing blood through semi-lunar valves into the arteries. Both sides of the heart fill and empty together
Pulmonary vein:
Carries oxygenated blood
To heart
Into left artium
Superior and inferior vena cava:
Carries deoxygenated blood
To heart
Into right atrium
Aorta:
Carries oxygenated blood
To body
From left ventricle
Pulmonary artery:
Carries deoxygenated blood
To lungs
From right ventricle
What is the septum
dividing wall of the heart
What is diastole
Heart relaxes
What is systole
Atria contract, followed by ventricles contracting
What is the order of valves opening and closing
Atrioventricular valves close, semilunar valve opens, semilunar valve closes, atrioventricular valve opens
What is a heart beat - what is it measured by
1 - blood is forced against atrioventricular valve as ventricles contract
2 - backflow of blood closes semilunar valves
Measured by a stethoscope
Explain what happens to control the basic rhythm of the heart
Sino-atrial node (SAN) causes atria to contract
Wave of depolarisation is picked up by the atrioventricular node (AVN), where it is held for a slight delay, before stimulating bundle of his (purkyne fibres), wave travels to apex, of heart, contraction starts from the apex upwards.
What is an electrocardiogram (ECG)
measure spread of electrical excitation through the heart. Used to diagnose heart conditions
How does an electrocardiogram work?
electrodes are stuck to skin, signal from electrodes is sent to machine which sends an ECG
What is the sequence of waves in an ECG
P (Electrical activity during atria systole) QRS (T = Ventricular repolarisation) (Q-T = ventricle contraction time) (T-P = filling time)
Tachycardia
Heartbeat is rapid
treated by medication or surgery
Brachycardia
Slow heart rate
Fitness
Treated by artificial pacemaker
Ectopic heartbeat
Extra heartbeats out of the normal rhythm
Common
Linked to conditions when frequent
Atrial fibrillation
Atria contract very quickly, but not effectively, only some impulses are sent to ventricles
Ventricular fibrillation
Heart attack, no QRS, ventricles do not contract enough to circulate blood
Unconscious/death
need defibrillator - shocks heart into normal rhythm
