3.2 Transport in animals Flashcards
What are the two types of circulatory systems?
Open or closed.
Define a closed circulatory system
Blood is confined in blood vessels only.
Give examples of organisms that have a closed circulatory system
Fish and Mammals
Give examples of organisms that have an open circulatory system
Insects
What are the two types of closed circulatory systems?
Single closed circulatory system or Double closed circulatory system.
Define single closed circulatory system
Consists of a heart with two chambers, meaning the blood passes through the heart once for every circuit of the body.
Define double closed circulatory system
The heart has four chambers and blood passes through the heart twice for every circuit of the body
What are some advantages of a double circulatory system?
Delivers oxygen and nutrients quickly to the parts of the body where they are needed.
What are some disadvantages of an open circulatory systems?
-Blood pressure is low and blood flow is slow
-Circulation of blood may be affected by body movements or lack of body movements
What are some advantages of the a closed circulatory system?
-Higher pressure so that blood flows more quickly
-More rapid delivery of oxygen and nutrients
-More rapid removal of carbon dioxide and other wastes
-Transport is independent of body movements
What is the function of arteries?
To move blood away from the heart to the rest of the body
Describe the structure of arteries.
-Thick walled to withstand high blood pressure,
-Contain elastic tissue which allows
them to stretch and recoil thus smoothing blood flow,
-Contain smooth muscle which
enables them to vary blood flow,
-Lined with smooth endothelium to reduce friction and ease flow of blood
What is the function of arterioles?
They feed blood into the capillaries
Describe the structure of arterioles.
Have thinner and less muscular walls.
What is the function of capillaries?
The site of metabolic exchange
Describe the structure of capillaries.
-Only one cell thick for fast exchange of substances
What is the function of venules?
Connect blood from the capillaries into the veins
Describe the structure of venules.
Larger than capillaries but smaller than veins
What is the function of veins?
Carry blood from the body to the heart.
Describe the structure of veins.
-Contain a wide lumen to maximise
volume of blood carried to the heart, -Thin walled as blood is under low pressure,
-Contain valves to prevent back-flow of blood, no pulse of blood meaning there’s little elastic tissue or smooth muscle as there is no need for stretching and recoiling
Define hydrostatic pressure.
The pressure that a fluid exerts when pushing against the sides of a vessel or container
Define lymph.
The fluid held in the lymphatic system, which is a system of tubes that returns excess tissue fluid to the blood system.
Define oncotic pressure.
The pressure created by the osmotic effects of the solutes.
What is Blood plasma, and what does it contain?
Plasma is the fluid portion of the blood, it contains dissolved substances such as oxygen, carbon dioxide, minerals, glucose, amino acids, hormones and plasma proteins.
Also contains red blood cells (erythrocytes) White blood cells and fragments called platelets.
How is tissue fluid similar to blood plasma?
Contains dissolved oxygen and carbon dioxide, but does not contain many blood cells or plasma proteins.
How is tissue fluid formed?
-At arterial end, blood has high hydrostatic pressure.
-The pressure pushes blood fluid out of capillaries through capillary wall. The fluid can leave through tiny gaps between cells and capillary walls.
-Blood cells and platelets too big to be pushed out of capillary
-Tissue fluid surrounds body cells, so exchange of gasses can happen through plasma membranes
How does tissue fluid return to the blood?
-The blood pressure at venous end of the capillary is much lower,
-allows some of the tissue fluid to return to the capillary carrying carbon dioxide and other waste substances into the blood
What happens to tissue fluid that doesn’t re-enter the blood
-Some tissue fluid is directed into another tubular system: The lymphatic system
-This drains excess tissue fluid and returns it to blood via subclavian vein in chest.
What is the fluid called thats found in the lymphatic system and what is it composed of?
Called Lymph, similar in composition to tissue fluid. Contains more lymphocytes, as they are produces in lymph nodes.
What are Lymph nodes?
Swellings found at intervals along the lymphatic system which have an important part to play in the immune response.
How does the oncotic pressure have an affect on movement of fluid in capillaries?
-Oncotic pressure of blood tends to pull water back into the blood (has a negative figure)
-Oncotic pressure of the tissue fluid pulls water into the tissue fluid.
Where are the atrio-ventricular valves and what is their function?
Valves between the atria and the ventricles
What is the function of the semilunar valves
Valves that prevent blood reentering the heart from the arteries.
What type of muscle is found in the walls of the heart?
Cardiac muscle.
Which side of the mammalian heart pumps oxygenated blood to the body?
The left side.
Which side of the mammalian heart pumps de-oxygenated blood to the lungs?
The right side.
Describe the external features of the mammalian heart.
-Made of dark red muscle called Cardiac muscle
-Atrium above ventricles
-Coronary arteries on the surface of heart
-At top of heart is tubular blood vessels, veins that carry blood into the atria
What is the function of coronary arteries?
Supply oxygenated blood to the heart muscles
What happens when the coronary arteries are constricted?
Reduces the delivery of oxygens and nutrients such as fatty acids and glucose. This may cause Angina or a heart attack
Describe the four chambers of the heart.
-Two upper chambers are atria, receive blood from major veins.
-Two bottom chambers are ventricles
Describe the course of how deoxygenated blood flows through the heart.
-Deoxygenated blood from body flows through Vena Cava into right atrium
-Flows through Atrio-ventricular valves into ventricles.
-Deoxygenated blood leaves right ventricle through the Pulmonary artery to lungs through Semilunar valves
Describe how oxygenated blood flows through the heart.
-Oxygenated blood from the lungs flows through Pulmonary veins into left atrium
-Down to ventricles through Atrio-ventricular valves
-Oxygenated blood leaves left ventricle through Aorta to body through Semilunar valves
Where are the Tendinous cords in the heart and what are their functions?
-Tendinous cords are attached to the valves , they prevent the valves from turning inside out when the ventricle walls contract.
Where is the Septum in the heart and what are their functions?
Septum separates the ventricles from each other
-This ensures oxygenated blood in the left side and deoxygenated blood in the right side are kept separate.
How does cardiac muscle create blood pressure?
Cardiac muscle contracts, creates pressure in the blood, higher the pressure created in the heart , further it will push the blood
Describe the structure and function of the Atria.
-Muscle of atrial walls are thin
-Because these chambers do not need to create much pressure.
-Function: receive blood from the veins and push it into the ventricles