Transport in animals Flashcards
What muscle is the heart made out of?
dark muscle called cardiac muscle
What are the two main pumping chambers?
ventricles and atria
What do coronary arteries do?
supply oxygenated blood to the heart muscles
What happens when arteries restrict blood flow?
due to build up of fatty acids causing angina and a heart attack
What blood vessels are above the heart?
tubular blood vessles
What do tubular blood vessels do?
veins that carry blood into the atria and arteries that carry blood away from the heart
what do tendinous cords do?
prevent the valves from turning inside out when the walls of the ventricles contract
what separates the two sides of the heart and why
septum
ensures deoxygenated blood and oxygenated blood is kept separate
what do semilunar valves do?
semi-lunar valves prevent blood returning to the heart as the ventricles relax
What does the mitochondria between the muscle fibrils do?
supply energy for contraction
What are the mitochondria divided by?
intercalated discs which facilitate synchronised contraction each nucleus is divided into contractive units called sarcomeres
What do valves do?
they stop backflow and ensure blood flows in right direction, they open and close due to changes in the blood pressure
What causes the pulse
the pressure created when the left semilunar valve is closed
Where is the SAN?
at top of the right atrium
What is a sino-atrial node (SAN)
its a small patch of tissue that generates electricity by imitating a wave of excitation at regular intervals - pacemaker
what does a electrocardiogram do?
monitors activity of the heart
What is the need for a transport system
- Size – larger organsims cell is further from its surface the diffusion pathway in increased and the rate reduced and diffusion is too slow to supply all the requirements, outer cells use up the supplies
- Surface area to volume ratio- lager animals have a smaller surface area to volume ratio which means each gram of tissue has a smaller area of body surface for exchange
- Level of metabolic activity – if animal is active it needs a good supply of oxygen for movement and warmth if a mammal
what are the features of a good transport system
- Fluid is transport the stuff
- A pump to create pressure that will push the fluid around the body
- Exchange surfaces that enable substances to enter the blood and leave it again where they are needed
- Tubes or vessels to carry the blood by mass flow
- Two circuits one to pick up oxygen and another to deliver it to the tissues
describe the pathway of a single circulatory system
heart - gills - body - heart
describe the pathway of a double circulatory system
- Double = heart-body-heart-lungs-heart
- Heart-body = systemic
- Heart-lungs=pulmonary
what are the advantages of double circulation and disadvantages of single circulation
- Blood pressure drops as blood flows through tiny capillaries of gills
- Low pressure therefore foes no flow very quickly
- Rate at which gaseous exchange occurs is limited
+ increased pressure therefore it flows more quickly
+ faster and more efficient as it is pumped twice
+ systemic can have a higher pressure then pulmonary so at various parts the pressure can vary - Pressure must not be too high in the pulmonary circulation otherwise it could damage the delicate capillaries in the lungs
what happens in a open circulatory system
- Blood not always held within the blood vessels but circulates through the body cavity so that the tissues and cells are bathed directly in blood
what is the heart in the open circulatory system
- Some animals movement effects the circulation in other animals such as insects they have a pumping system like the heart, this is a long muscle tube that lies under the dorsal surface of the body., the blood enters the heart through ostia these are pores, the heart then pumps the blood towards the head via peristalsis and at the forward end of the body the blood pours into the body cavity, some insects have open ended tubes that attach to the heart and direct blood towards the active part of the body
what is the disadvantages of an open circulatory system
- Blood pressure is low therefore blood flow is slow
- Circulation of blood is affected by body movements or lack of body movements
what are the advantages of an closed circulation system
- Higher pressure so blood flows more quickly
- More rapid delivery of oxygen and nutrients
- More rapid removal of carbon dioxide and other wastes
- Transport is independent to body movements
what do all blood vessels have
- All blood vessels have a inner layer made out of a single layer of cells called the endothelium – this is smooth in order to recue friction with the flowing blood
describe the artery
Inner layer (tunica intima) consist of a thin layer of elastic tissue which allows the wall to stretch then recoil in order to maintain blood pressure Middle layer (tunica media) consists of thick layer of smooth muscle Outer layer (tunica adventitia) thick layer of collagen and elastic tissue this provides enough strength to withstand high pressure and recoil to maintain the pressure Small lumen to maintain pressure and inner wall is folded to allow lumen to expand when blood flow increases Thick wall to withstand the pressure
describe the veins
Large lumen, ease the flow of blood
The walls have thinner layer of collagen, smooth muscle and elastic tissue as they do not need to stretch and recoil, and they are not actively constricted to reduce blood flow
Have valves this helps blood flow back to the heart and prevent it from flowing in the opposite direction
Walls are thin and veins can be flatted by the action of the surrounding skeletal muscle, this contraction of the muscle applies pressure to the blood and forces the blood to move along in a direction which the valves determined
describe the job of the arterioles and what they look like
- Small blood vessels that distribute the blood from an artery to the capillaires
- -layer of smooth muscle and contraction of this muscle will constrict the diameter of the arteriole therefore increasing resistance to flow and reducing the rate of flow of blood
- The constriction can be used to divert the flow of oxygen to areas that depend more oxygen
describe the job of the venules and what they look like
- From the capillaries the blood flows into the venules
- Collect blood from the capillary bed and lead into the veins
- Consist of thin layers of muscle and elastic tissue outside the endothelium and a thin layer of collagen
what is plasma
- Blood contains a liquid called plasma which contains many blood cells as well as oxygen and carbon dioxide, platelets
whats another word for red blood cells
erythrocytes
whats another word for white blood cells
leucocytes
what is tissue fluid and what does it do
- It is formed by the plasma leaking from the capillaries
- Surrounds the cells and gives them what they need
how is tissue fluid formed
- Blood flowing into an organ or tissue is contained in the capillary
- At the arteriole end (end near artery) the blood has high hydrostatic pressure but low oncotic pressure therefore the overall net movement is outwards, the high hydrostatic pressure pushes the blood fluid out of the capillaries through the capillary wall, the tiny gaps between cells allows it to leave
- The fluid that leaves consists of plasma with dissolved oxygen and nutrients everything else remains in the blood as they are too large to be pushed out through the gaps in the wall
- The tissue fluid surrounds the body cells and exchange occurs by diffusion
- At the venule end the hydrostatic pressure is lower than the oncotic pressure therefore the net is inflow this allows the tissue fluid to return and get rid of the wastes into the blood
what happens to the tissue fluid which does not re-enter the blood
- Some is directed to another tubular system called the lymph system
- Drains excess tissue fluid out of the tissue are returns it to the blood system in the subclavian vein in the chest
- The fluid in the lymphatic system is called lymph and is in similar composition to the tissue fluid but it will contain more lymphocytes
- Lymphocytes are produced in the lymph nodes
what does blood plasma have hydrostatic oncotic cells proteins fats
hydrostatic - high oncotic - more negative cells - RBS, lymphocytes, neutrophils proteins - plasma proteins fats - transported in lipoproteins
what does tissue fluid have hydrostatic oncotic cells proteins fats
hydrostatic -low oncotic - less negative cells - some neutrophils especially in infected areas proteins - few proteins fats - few fats
what does lymph have hydrostatic oncotic cells proteins fats
hydrostatic - low oncotic - less negative cells - lymphocytes proteins - few proteins fats - more fats especially near digestive system
how do you work out pressure
- Get net hydrostatic pressure
- Get net oncotic pressure
- Net hydrostatic pressure – net oncotic pressure
what are the external features of the heart
- Cardiac muscle
- Ventricle
- Atria
- Coronary arteries – supply oxygenated blood, if restricted can cause problems such as angina or a heart attack (myocardial infarction)
what are the internal features of the heart
atria ventricles atrioventricular valves semilunar valves AVN SAN
how does the heart work basically
- Vena cava brings deoxygenated blood from the body into the right atrium
- The blood from the right ventricle is pushed into the pulmonary artery which then goes on the pulmonary circulation to the lungs to get oxygenated
- Pulmonary vein brings it back into the left atria
- Left ventricle pumps the oxygenated blood into the aorta which takes it to the rest of the body
- Atrioventricular valves – between the atria and the ventricle, tendinous cords are attached to these valves
- Semilunar valves are between the ventricles and the arteries – prevent blood from returning once the ventricles relax
describe the atria
thin walls as the chambers do not need to create much pressure as their function is to receive blood and give it to the ventricles
describe the left ventricle
wall is thicker than right ventricle as need to overcome pressure and resistance of the systemic circulation and pump to the whole body
describe the right ventricle
wall is thicker than the atria so can pump blood out of the heart, but the blood does not need to travel very far therefore it is not that thick
describe the cardiac muscle structure
- Consist of fibres that branch producing cross-bridges these spread stimulus around of the heart and ensure the muscle can produce a squeezing action
- Mitochondria between the myofibrils to supply energy for contraction
- Muscle cells are separated by intercalated discs which give synchronised contraction
- Each cell has a nucleus and is divided into contractile units called sarcomeres
describe the cardiac cycle
- Atrial systole – the ventricles are relaxed, the atria fill up with blood decreasing their volume and increasing their pressure, this causes the atrioventricular valves to open and the atria contract pushing the blood into the ventricles, this is because pressure is higher in the atria than in the ventricles which forms a pressure gradient causing the blood to flow downwards
- Ventricular systole – the ventricles contract and atria relax, this is due to the ventricles filling up with the blood and decreasing their volume and increasing their pressure, the atrioventricular valves close in order to prevent backflow, the semi-lunar valves open and the blood flows out of the ventricles into the arteries
- Diastole- the ventricles and atria relax due to an increase in volume and a decrease in pressure, the semi lunar valves close preventing backflow, the atria begin to fill up again due to high pressure in the vein
extra atrioventricular stuff we need to know
- Remain open while the atria contact but close when they relax
- Closure is caused by a swirling action in the blood around the valves when the ventricle is full
- Ventricles begin to contract and pressure increases, once the pressure increases past that of the atria the blood will rise upwards due to the pressure gradient but the valves shut
- The tendinous cords prevent the valves from turning inside out
extra semilunar valves we need to know
- Open as pressure in the ventricles is higher than in the arteries
- Once the blood is gone the muscles relax and the elastic tissue in the walls of the ventricles recoil this returns the ventricles to its original size,
- The pressure drops in the ventricles and the blood starts to return
- The valves are closed by the blood collecting in the pockets of the valves
why do we need to co-ordnate the cardiac cycle
- Atria and ventricles muscles each have their own frequency that they contract to, the atria have a slightly higher frequency
- If they did not have this property then the contraction of the chambers would not be synchronised this is called fibrillation
describe the contraction of the atria and ventrcles
- SAN genertates the wave of excitation
- Spreads over both walls of the atria by travelling along the membranes of the muscle tissue
- This causes the cardiac tissue to contact
- This is atrical systole
- At the base of the atria the tissue is non-conductive therefore it cannot spread to the ventricles but the wave of excitation reaches the AVN
- There is a pause of the wave of excitation this is because if there was not pause both atria and ventricles would contract at the same time and the blood would not go anywhere
- The wave of excitation from the AVN travels down the purkyne tissue this is conductive
- The wave of excitation foes down to the apex of the heart and moves upwards causing the ventricles to contract from the base
- Pushes the blood upwards into the arteries
describe the parts of an electrocardiogram
- P – shows the excitation and contraction of the atria
- QRS complex – shows the excitation and contraction of the ventricles
- T – shows the relaxation and diastole of the ventricles and atria
- P-R – is the travel of the wave from the wave of excitation from the SAN to the AVN
- R-T – time taken for the wave to go down the purkyne tissue and ventricular systole occur
