Bio Chapter 6 - transport Flashcards
What are the 4 main components of blood
Plasma, red blood cells ,white blood cells and platelets
what is plasma
yellowish liquid in blood that contains mainly dissolve substances such as biological molecules and vitamins
what are the functions of plasma
plasma transports blood cells around the body
nutrients from the small intestine to the large intestine
metabolic waste products from organs where they are produced
hormones from endocrine glands to target organs
what are platelets
fragments of cytoplasm containing an enzyme that catalyses the conversion of fibrinogen to fibrin threads
what is the function of red blood cells
transports oxygen from the lungs to the other parts of the body
describe the adaptations of RBC - haemoglobin
RBCs contain haemoglobin that combines reversibly with oxygen
in the lungs where the oxygen concentration is high, haemoglobin binds with oxygen to form oxyhaemoglobin
in tissues where the oxygen concentration is low, oxyhaemoglobin releases oxygen to tissue cells
describe the adaptations of RBC - shape
the biconcave shape of RBC increases the surface area to volume ratio which increases the rate of absorption and release of oxygen
it also enables the RBC to be flexible and can change into a bell-shaped so that it can easily flow through narrow blood capillaries
there is no nucleus in RBC which means theres more haemoglobin storage
what is the function of phagocytes
to perform phagocytosis
- process by which a white blood cell engulfs and destroys foreign particles such as bacteria
what is the function of lymphocytes
- recognize foreign particles
- destroy disease-causing organisms such as bacteria and viruses
- cause bacteria to clump together for easy ingestion by phagocytes
- neutralize toxins produced by bacteria
why must blood clot?
blood exposed to air will clot and coagulate to form a solid clot
clots seal the wound to prevent excessive blood loss
clots prevent foreign particles from entering the bloodstream
how does blood clot
platelets convert the soluble protein, fibrinogen to insoluble threads of fibrin which involves enzymes
fibrin threads entangle blood cells and the whole mass forms a clot or scab that seals the wound preventing entry of microorganisms and excessive loss of blood
why do people get organ/tissue transplant?
when a person’s tissue or organ is damaged or diseased, it can be replaced by a healthy tissue or organ from a donor
what is tissue rejection?
it is when foreign tissue may be recognized by the white blood cells and they respond by producing antibodies to destroy the foreign tissue
what are the solutions to tissue rejection?
if the tissue to be transplanted comes from a donor, tissue match is necessary to reduce risk of rejection
both tissues of donor and recipient must be as genetically similar as possible
use of drugs which inhibit the responses of the recipient’s immune system
what is the function of the heart
blood is kept circulating throughout the body by means of a muscular pump
what is the process of the heart pumping blood?
when the heart relaxes it fills up with blood
when it contracts the blood is squeezed out with great force
the blood then circulates throughout the blood vessels that direct the blood flow around the body
what is the function of the arteries
the blood vessels that carry blood away from the heart
from the heart, what is the process of the arteries transporting blood?
the large artery that leaves the left side of the heart is the aorta that branch out to form smaller arterioles
what is the blood pressure and speed of blood flow of in the arteries
arteries need to be able to withstand the high pressure of the blood forced out of the heart that is fast-moving
the arteries carry oxygenated blood away from the heart
what are the 3 adaptations of the arteries
thick, muscular and elastic walls - thicker arteries closer to the heart
- enable arteries to withstand the high bp inside it as blood is forced out of the heart
- it makes the artery wall elastic enabling its wall to stretch and recoil which helps push the blood in spurts along the artery and gives rise to the pulse
what is the function of arterioles
divide and branch out to form very tiny blood vessels called capillaries
what are blood capillaries
microscopic blood vessels that are found between the cella of almost all tissues
what is the function of blood capillaries
facilitate the exchange of substances between blood and tissue cells in the body
what is the process of exchange of substances in the capillaries?
capillary walls are highly permeable - wall is one cell thick thus short diffusion distance - and enables certain substances to diffuse quickly through them
small arteries branch out to form capillaries
numerous branches provide a large surface area for the exchange of the blood and tissue cells
when an arteriole branches into many capillaries the total cross sectional area of the blood vessels increase - lowers blood pressure in the capillaries & the flow of blood is slowed down giving more time for the exchange of substances
what is the function of the vein
carries deoxygenated blood back to the heart
how are veins formed?
they are formed when venules join together
why is the bp of the veins much lower than in the arteries?
blood moves much more smoothly and slowly in the veins compared to the artery where blood is forced out from the heart at fast speed and high pressure
what are the adaptations of the veins
walls of the veins do not need to be as thick as arteries - thin walls
contain less elastic tissue and instead have internal valves along their length to prevent backflow of blood
what are the adaptations of the veins
walls of the veins do not need to be as thick as arteries - thin walls
contain less elastic tissue and instead have internal valves along their length to prevent backflow of blood
what is the size of the lumen in arteries and veins
arteries - small lumen
veins - large lumen
what could happen if we sit for too long
pressure can build up in the veins of the lower limb which causes poor blood circulation and blood to pool in the legs
what happens during pulmonary circulation?
from the heart, the pulmonary arteries carry blood to the lungs
oxygen enters the blood at the lungs
oxygenated blood is returned to the blood by pulmonary veins
what happens during systematic circulation
oxygenated blood leaves the left side of the heart and is distributed by the arteries to all parts of the body excld lungs
veins carry blood from all parts of the body back to the right side of the heart
what is the atria
the atria are the two upper chambers of the heart - left/right atrium
the atria receive blood from the veins
what are the features of the atria?
the atria have comparatively thin muscle walls since they only force blood into the ventricles that lie directly below them and thus doesnt require high pressure
what are the features of the ventricles
have comparatively thick muscular walls
left ventricle muscle is much larger because it pumps blood around the whole body and requires more pressure
right ventricle has thinner walls than the left ventricle since it only pumps blood to the lungs
what is the median septum?
muscular wall that separates the right and left side of the heart
what is the function of the median septum
prevents mixing of deoxygenated blood in the right side of the heart and oxygenated blood in the left side of the heart as this could decrease the amount of oxygen in the body
what is the function of the biscuspid valve
prevents backflow of blood from the left ventricle to the left atrium
what is the function of the tricuspid valve
prevents the backflow of blood from the right ventricle to the right atrium
what is the function of the aortic valve
prevents backflow of blood from the aorta to the left ventricle
what is the function of the pulmonary valve
prevents backflow of blood from the pulmonary artery to the right ventricle
what paths does blood take through the heart?
- deoxygenated blood from the body enters the right atrium by 2 venae cavae
- upp vena cava transports blood from the head, neck and arms back to heart
- lower vena cava transports blood from the rest of the body excld lungs back to the heart - from the right atrium the blood passes through the tricuspid valve to the right ventricle
- tricuspid valve containts three flaps that point downward toward the right ventricle and are attached to the walls of the right ventricle by the chordae tendinae - from the right ventricle, the blood leaves the heart by the pulmonary artery to the lungs
- pulmonary vein transports oxygenated blood from lungs to the left atrium
- blood passes from the left atrium through the bicuspid valve
- has two flaps that point down towards the left ventricle
- chordae tendinae prevent the flaps from being reverted into the left atrium when right ventricle muscles contract - from the left ventricle blood leaves the heart and enters the aorta to be distributed around the body through different arteries
- two coronary arteries emerge from the aorta and brings oxygen and nutrients to the heart muscles
what happens when there is a hole in the heart?
some infants born with hole in the heart present in median septum separating the left atrium & right atrium or left ventricle & right ventricle
blood will flow through the hole mostly from the left side to right side of the heart as pressure from the left side is higher than in the right
hence there is mixing of oxygenated blood and deoxygenated blood and lesser oxygen is transported to body cells for respiration
How does blood flow through the heart?
- The atrial muscles contract forcing blood into the ventricles
- After awhile, the ventricle muscles contract and there is an increase in pressure inside the ventricles. Bicuspid and tricuspid valves close to prevent back flow of blood to the atria causing a ‘lub’ sound. The semi-lunar valves open and blood flows from the right ventricle and left ventricle to the pulmonary artery and aorta respectively
- As the ventricle muscles contract, the atrial muscles relax. The right atrium receives blood from venae cavae while the left atrium receives blood from the pulmonary veins
- The ventricle muscles relax and there is a fall in pressure
- this causes the semi-lunar values to close to prevent backflow of blood from the pulmonary artery and aorta and ventricles
- produces a softer ‘dub’ sound
- bicuspid and tricuspid valves open and blood flows from atria to ventricles - The atrial muscles open again and the cycle repeats
What is pulse?
Pulse is produced after every ventricular contraction as the heart pumps blood
What are the arteries leaving the heart?
Pulmonary arteries from right ventricle
Aorta from left ventricle
Which arteries arise from the aorta?
Arteries to head, neck and arms
Hepatic artery to liver
Artery to stomach and intestines
Renal arteries
What are the main veins that return blood to the heart?
Pulmonary veins bring blood from the lungs to the left atrium of the heart
Upper vena cava returns blood from the head, neck and arms to right atrium
Lower vena cava brings blood from the rest of the body to the right atrium
Which veins in the lower parts of the body transport blood to the lower vena cava?
Renal vein transports blood from the kidneys
Hepatic vein transports blood from the liver
Do veins in the small intestine open directly to the lower vena cava?
They do not open directly but instead unite to form the hepatic portal vein that arises from the wall in the small intestine at one end and gives rise to capillaries in the liver at the other end
What happens during a heart attack?
blood flow to a part of the heart may be completely blocked and it may not receive enough oxygen and nutrients and dies
extensive heart muscle damage is often fatal as the heart is no longer able to pump blood to various parts of the body
What are the causes of coronary heart disease?
fatty substances such as cholestrol and saturated fats may be deposited on the inner surface of the coronary arteries or atherosclerosis
this narrows the lumen of those arteries and increases the blood pressure
those arteries develop a rough inner surface and there is an increased risk of blood clot being trapped in the artery and supply of blood and oxygen to heart muscles may be completely cut off
what happens when there is a lack of oxygen?
oxygen is needed in aerobic respiration to release energy for the activities of the muscle cells
without oxygen heart muscle cells are damaged and a heart attack occurs
what are the risks of coronary heart disease?
- smoking
- cigarette smoke contains carbon monoxide and nicotine = increased risk of coronary heart disease
- nicotine increases blood pressure and risk of blood clotting in the arteries - unhealthy diet
- a diet high in cholestrol, sat fat and salt = increased risk of coronary heart disease - genetic factors
- high bp and high cholestrol can run in the family - age
- risk of coronary heart disease increases with age
- majority of people suffering from chd are 65 y/o and above - sedentary lifestyle
- inactivity causes the build up of fatty deposits that block the arteries = increased risk of coronary heart disease
