Chapter 8 ~ Transport In Animals Flashcards
Why are specialise transport systems needed
For high metabolic demand
To maintain steep concentration gradient
To overcome a low surface area to volume ratio
To allow diffusion across a large distance
Transport a hormones and enzymes
Transport waste products
What is an open circulatory system?
It is not enclosed in blood vessels
The heart pumps the blood around the body under pressure and blood returns directly to the heart
What is a closed circulatory system?
Blood is enclosed in blood vessels
The heart pumps blood around the body and the body returns it to the heart
Substances will move between the bloodstream and and tissues at the capillary and arteries take blood away from the heart and organs veins take blood from the tissue back to the heart
What is a single closed circulatory system
Blood flows through the heart and is pumped out to travel all around the body before returning to the heart
ONCE
What is the double circulatory system?
Blood travels in two loops
Blood pumped from the heart lungs pick up oxygen and unload CO2
Blood flows through the heart and is pumped out to travel all around the body
Blood essentially travels twice
What is elastic fibre?
Composed of elastin which can stretch and recoil providing flexibility
What is smooth muscle?
Contracts or relaxes, changing the size of the lumen
What is collagen?
Provides a structural support to maintain the shape and volume of the vessel
What are arteries?
Arteries carry oxygenated blood away from ❤️
What are the exceptions of carrying oxygenated blood for arteries?
Pulmonary artery, which carries the deoxygenated blood from the heart to the lungs, and during pregnancy that umbilical artery carries deoxygenated blood from the fetus to the placenta
Does the arteries carry blood under high pressure or low pressure
High pressure
What is a structure of the artery?
Is made of elastin fibre, which allows the walls to expand, allowing continuous flow of blood
It has smooth muscle, which allows easy blood flow
It is made up of collagen
Thick muscular wall containing lots of elastic tissue to withstand the force of high pressure of blood
Inner lining endothelium which is folded, allowing the artery to expand elastic boil recoil .
Small lumen to withstand high pressure
Explain vasconstriction
When the smooth muscle in the arteriole contract, it constricts the vessels, and prevents blood flowing into the capillary bed
Explain vasodilation
When the smooth muscle in the wall of an arteriole relaxes blood flows through into the capillary bed
What is the function of the arteriole
It links the artery to the capillary and vasoconstriction and vastdilation
What is the structure of the capillary?
. Thin endothelium and narrow lumen for short diffusion
Many capillaries, which are highly branched forming a large network for a large surface area
Single endothelial cell thick, allowing a short layer of diffusion
Small holes enabling exchange of substance
Blood entering the capillary is
Blood leaving the capillary is
Oxygenated
Deoxygenated
Function of the vein
Carry deoxygenated blood away from cells towards the heart
What what are the exceptions of the veins carrying the deoxygenated blood?
The pulmonary vein and umbilical vein carry oxygenated blood
Structure of the veins
Lots of collagen and little elastic fibre
Large lumen and thinner walls as blood is flowing LOL pressure
Valves which prevent the backflow of blood
What does venules do
Link capillaries with veins
Structure of venules
Thin walls with smooth muscle
Functionof valve
Prevent backflow
What does blood consist of?
Plasma, erythrocytes, platelets, leuocytes
What is tissue fluid?
It is fluids surrounding tissues formed from blood plasma
What is hydrostatic pressure?
Pressure exerted by fluid
What is oncotic pressure?
Tendency of water to move into blood via osmosis
Explain the process of tissue fluid formation
Arterial end:
There is a high hydrostatic pressure which is greater than oncotic pressure.
This forces fluid and dissolved substances out of the capillary forming tissue fluid
Venous end:
Water potential is lower inside capillary compared to tissue fluid.
This means there is a high oncotic pressure which is greater than hydrostatic pressure.
This forces water out
What is the heart made up of?
Cardiac muscle, which contracts and relaxes in a regular rhythm
What does the septum do?
It prevents the mixing of oxygenated and oxygenated blood
What is the heart surrounded by?
Inelastic pericardial membranes which help prevent the heart overflowing with blood
Explain the process of the oxygenated blood entering the right atrium of the heart
Enters the right atrium from the vena cava at low pressure
Blood flows in and the pressure buildup until the atrial ventricular valve opens and lets blood pass into the right ventricle
The atrium and ventricle are both filled and the atrium contracts forcing all of the blood into the right ventricle
The right ventricle begins to contract and the atrial ventricular valve closes and the right ventricle pumps blood through the semilunar valve into the pulmonary artery which is transported back into the lungs
What do the tendinous cords do
They make sure the valves are not turned inside out by the pressure exerted as the ventricle contracts
Explain the process of oxygenated blood from the lungs to the left atrium from the pulmonary vein
It enters the left atrium from the pulmonary vein.
Pressure in the left and build and the bicuspid valve opens and left ventricles will fill with oxygenated blood
The atrium and ventricle both fill up and the left atrium contracts, forcing all the blood into the left ventricle
The left ventricle contracts and pumps oxygenated blood through the semilunar valve into the aorta and around the body
Why is the muscular wall of the left side of the heart much thicker than the right?
Because the left side carries blood all around the body
What is a cardiac cycle?
It describes the events in a single heartbeat, which lost around 0.8 seconds
What happens during diastole?
Both the atria and ventricles are relaxed so the pressure is low in both chambers
The semi lunar valves are closed as the pressure is higher in the arteries in the chambers
What is then return to the heart and the atria filled with blood?
What are the 2 types of systole ?
Explain both
atrial systole:
The atria contracts while the ventricles relax
This decreases the volume inside the atria which increases pressure
Increased pressure forces the atrial ventricular valves to open and pushes blood into the ventricles
Ventricular systole:
The ventricles contract and atria relaxes
Decreases the volume inside the ventricles and increases the pressure
This forces the atrial ventricular valves to close and causes the semilunar valves to open
Blood is forced out of the ventricles and into the arteries
What is the formula for cardiac output?
Heart rate x stroke, volume
What are heartbeats made by?
The blood pressure closing the heart valve
Where is the first sound of the heart come from?
As blood is forced against the atrial ventricular valves as the ventricle contracts
What is the second sound of of the heart come from
Backflow of the blood causes semi Luna valves in the aorta and the pulmonary artery as the ventricle relax
What does myogenic mean?
the heart has its own intrinsic rhythm. At around 60 bpm
Where is the SAN located and what happens?
It is located at the right atrium and is known as a pacemaker
What does a bundle of his do?
It splits into two branches and conducts the wave of excitation to the apex of the heart
Explain how a basic rhythm of the heart is caused
① a wave of electrical excitation at SAN CAUSES THE ATRIA TO CONTRACT INITIATING A HEARTBEAT
② electrical activity is picked up by the AVN which has a slight delay and then stimulates the bundle of his
③ the bundle of his conducts a wave of citation to the apex
④ at the apex, purkyne fibres spread through the walls of the ventricles this spread the excitation which causes contraction of ventricles
What is the purpose of an ECG?
To measure electrical excitation through the heart
How does an ECG work?
Electrodes are placed against a patient chest and the change in electrical activity is displayed as an electrocardiogram
Explain the ECG of tachycardia
The heartbeat is very rapid over 100 bpm
The increase heart rate is a normal response to exercise, excitement, stress or drugs
It is elevated heart rate for no reason
Sometimes, sometimes the heart rate is so high, that little blood is actually pumped
Treatment can be relaxation therapy or b blocker
Explain bradycardia ECG
The heart rate slows down to below 60 bpm
Reduce heart rate could indicate good, aerobic, fitness, or maybe caused by drugs, like tranquilizers or beta blockers
It could cause risk of blood clots
What is a ectopic heartbeat ECG
Extra heartbeats, which are out of the normal rhythm  most people have at least one a day
What a ter atrial fibrillation, ECG
An example of an arrhythmia, which means an abnormal rhythm of the heart. Rapid electrical impulses are generated in the atria, which contract very fast. However, they don’t contract properly and as a result, the heart does not pump blood very effectively.
What is lymph?
It is 10% of the liquid which leaves blood vessels No
What is lymph?
It is 10% of the liquid which leaves blood vessels No
Explain the lymphatic system
Tissue fluid, which isn’t reabsorbed into the capillaries drains into the lymphatic system preventing fluid buildup. The system collects excess tissue fluid and returns it back into the bloodstream..
The lymph nodes intercept bacteria
Explain the structure of erythrocytes
It contains a biconcave shape with larger surface area which is available for diffusion
It has no nucleus and it contains haemoglobin
Explain the structure of haemoglobin
It is a globular conjugated protein with a tertiary structure consisting of four polypeptide chains each containing a haem group
Haemoglobin is red as it has iron binding to oxygen
Explain how oxygen binds to haemoglobin
Each polypeptide chain is bonded to a group which contains an iron ion which combines to one molecule of oxygen. This produces Oxy haemoglobin.
What is the purpose of of Oxy haemoglobin and what is the reaction to format?
To transport oxygen around the body
Hb + 402 → hb (O2) 4
Haemoglobin bind to oxygen with high affinity in the ______ and there is a _________ partial pressure of oxygen
Lungs
High
Haemoglobin bind to oxygen with low affinity in the ______ and there is a _________ partial pressure of oxygen
Tissues
No
Oxygen Association
. Oxygen binding into haemoglobin
Oxygen dissociation
Oxygen unbinding to haemoglobin
Explain positive cooperativity
Haemoglobin has a tertiary structure and each haem group can bind with one oxygen so it can carry 4 oxygen molecules when one binds the structure of the protein changes which increases the affinity of other three binding sites for oxygen
what is an oxygen dissociation curve?
It’s a graph plotting the partial pressure of oxygen against how saturated haemoglobin is with oxygen
Low oxygen concentration haemoglobin has a
‘low affinity for oxygen allowing it to release oxygen to respiring cells
Low oxygen concentration haemoglobin has a
‘low affinity for oxygen allowing it to release oxygen to respiring cells
High oxygen concentration
Low Affinity for oxygen
Fetal haemoglobin has a _________ affinity then adult haemoglobin so lies to the______
higher
Left
Explain the Bohr affect
Partial pressure of carbon dioxide increases
So hemiglobin has a low affinity for oxygen causing Oxy haemoglobin to dissociate more readily
Hi carbon dioxide concentration shifts the dissociation have to the _______ and is referred as the ________
Right
Bohr effect
Explain the chloride shift
Question for another day
