Chapter 06 - Transport in Humans Flashcards
What is blood made up of?
1) Plasma
2) Red blood cells
3) White blood cells
4) Platelets
Describe plasma
Plasma is a yellowish pale liquid that consists of water and other dissolved substances (glucose, salts, proteins, amino acids, fats, vitamins, hormones, excretory products, red blood cells and white blood cells)
Describe the functions of plasma
1) Transports RBC and WBC around the body
2) Transports nutrients from the small intestine to other parts of the body
3) Transports excretory products from their production organs to excretory organs for removal
4) Transports hormones from endocrine glands to target organs
What are the 4 adaptations of red blood cells?
1) Circular, biconcave shape – Increase SA:V
2) Contains haemoglobin – binds readily and reversibly with oxygen
3) No nucleus – More space for more haemoglobin
4) Flexible – Squeeze through narrow capillaries
What is the main function of red blood cells?
To transport oxygen molecules from the lungs to the rest of the body
What happens to the concentration of oxygen in the air at higher altitudes?
The concentration is lower resulting in a less steep concentration gradient between the lungs and the air causing the oxygen to diffuse more slowly into the lungs, reducing the amount of oxygen absorbed into the blood
What does the body do in response to lesser oxygen absorbed into the bloodstream?
To compensate for this, the body produces more RBC for more haemoglobin to increase the oxygen carrying capacity of the blood to ensure an adequate supply of oxygen for aerobic respiration to provide sufficient energy to meet the body’s needs
What are the 2 types of white blood cells?
1) Phagocytes
2) Lymphocytes
Describe the structure of white blood cells
White blood cells are irregular in shape, phagocytes have a lobed nucleus while lymphocytes have a round nucleus
What are the main 2 functions of white blood cells?
1) Antibody production
2) Phagocytosis
What do lymphocytes produce and what are the functions?
Antibodies can
1) recognise foreign particles
2) destroy disease causing organisms such as bacteria and viruses
3) cause bacteria to clump together for easy ingestion by phagocytosis
4) neutralises toxins produced by bacteria
What process do phagocytes carry out?
Phagocytosis - the process by which a white blood cell engulfs and destroys foreign particles. This process is to destroy bacteria by taking them into the cytoplasm through ingestion
What are platelets made of?
Fragments of cytoplasm
What do platelets do?
Platelets prevent excessive blood loss and the invasion of harmful organisms into the bloodstream
Describe the process of blood clotting
1) When blood is exposed to air, an enzyme is released by the platelets from the damaged tissues to activate the thombrin in the plasma
2) Thombrin catalyses the conversion of soluble fibrinogen into insoluble fibrin threads
3) Fibrin threads entangle to blood cells and the entire mass becomes a clot/scab
4) A clot prevents foreign/harmful substances from entering the bloodstream
What is tissue/organ transplant?
Replacement of damaged/diseased tissue/organ by a healthy one from a donor
Why would a recipient’s (receiving an organ/tissue) immune system reject the transplanted organ?
The recipient’s immune system treats the donor’s tissue/organ as a foreign entity, causing white blood cells to produce antibodies to destroy the transplanted organ/tissue
What are 3 measures to overcome the problem of tissue/organ rejection?
1) If a person suffers skin burns, healthy skin from another part of the same person’s body can be used to replace the damaged skin
2) A tissue match can be performed to ensue the tissues of the donor and recipient are highly genetically similar
3) Use drugs that can suppress the responses of the recipient’s immune system towards the foreign tissue
What do red blood cells have on their surface and in their plasma?
Antigens on the surface, antibodies in plasma (both contain special proteins in our body)
What are the 4 blood groups?
A, B, AB, O
What kind of letters are used to represent antigens and antibodies
Antigen: Caps
Antibody: no caps
What are the antigen(s) and antibody(ies) present in blood group A?
Antigen A, Antibody b
What are the antigen(s) and antibody(ies) present in blood group B?
Antigen B, Antibody a
What are the antigen(s) and antibody(ies) present in blood group AB?
Antigen A&B, no antibodies
What are the antigen(s) and antibody(ies) present in blood group O?
No antigens, Antibody a&b
If the antigen A binds with antibody a, what would the effect be?
Clumping of red blood cells
If the antigen A binds with antibody b, what would the effect be?
No clumping of red blood cells
If the antigen B binds with antibody a, what would the effect be?
No clumping of red blood cells
If the antigen B binds with antibody b, what would the effect be?
Clumping of red blood cells
Why is agglutination (clumping) dangerous?
The clumps can block small blood vessels and obstruct blood flow. Hence, matching blood types is important in blood transfusions to avoid clumping and potential health risks
What is transfusion?
Transfusion is the process of transferring fluid into a vein or an artery
What blood group can AB give to and receive from?
AB can only give to AB
but receive from AB, A, B and O (AB is greedy)
What blood group can A give to and receive from?
A can give to A and AB
and receive from A and O
What blood group can B give to and receive from?
B can give to B and AB
and receive from B and O
What blood group can O give to and receive from?
O can give to AB, A, B, O
and receive from O
(overly generous)
What is the heart and what happens when it relaxes and contracts?
A heart is a muscular organ that is responsible for pumping blood throughout the body
When the heart contracts, the blood is forced out with high pressure
When the heart relaxes, the heart chambers fill up with blood
What are arteries?
Arteries are blood vessels that carry blood away from the heart
What is the name of the large artery that leaves the left side of the heart?
Aorta, it branches to form smaller arteries
What kind of walls do arteries have and why?
Thick and muscular - withstand high blood pressure (because arteries receives blood directly from heart and blood is forced out)
Elastic - Stretch and recoil/spring back to propel blood in spurts along the artery (pulse)
What is constriction and dilation of the artery caused by?
The contraction and relaxation of muscles in the arterial wall
What happens to the lumen of the artery when the muscles in the wall of the arterial wall contract?
The lumen becomes narrower when it constricts, so less blood flows through it per unit time
What happens to the lumen of the artery when the muscles in the wall of the arterial wall relax?
The lumen becomes wider when it, so more blood flows through it per unit time
What kind of blood do arteries carry?
Oxygenated blood (except pulmonary arteries)
What are the smaller arteries called?
Arteries branches to form arterioles
Blood flows through the arterioles before entering the ____
capillaries
What are capillaries?
Microscopic blood vessels formed by arterioles and found between cells of almost all tissues
Why are capillaries highly branched?
To increase surface area to volume ratio for the exchange of substances between the blood and tissue cells. This also increases the total cross-sectional area of blood vessels, which lowers blood pressure in the capillaries
Are capillaries partially permeable?
Yes, this allows exchange of certain substances to take place
Why are capillaries only made up of a single layer of flattened cells?
To provide a short diffusion distance for substances to move across the capillary wall more rapidly
What do tiny spaces between tissue cells contain?
Tissue fluid which acts as a medium for exchange of substances between capillaries and tissue cells (cells that make up a tissue)
What does tissue fluid transport?
Dissolved substances such as oxygen and excretory products
Where do oxygen and nutrients diffuse from?
Oxygen and nutrients (e.g. glucose, amino acids) diffuse from the blood capillaries to the tissue fluid
Where do excretory products diffuse from?
Excretory and metabolic waste products (e.g. carbon dioxide) diffuse from the tissue cells into tissue fluid and then into capillaries for removal
Where do food substances and oxygen end up and where do waste products end up?
Food substances and oxygen ends up in the cells while waste products end up in the blood (transported by blood capillary)
Where does blood transport waste products?
To excretory organs for removal
Before leaving an organ/tissue, capillaries unite to form ____
Venules
Venules join together to form ____
Veins
Where do veins transport blood from?
Veins transports blood towards the heart
Why are the walls of veins not thick an muscular?
The blood pressure is lower, so blood flows more smoother and slower
Why do veins contain less elastic tissue?
Instead of stretching and recoiling, vein shave valves to prevent backflow of blood
What kind of blood do veins carry?
Deoxygenated blood
How is blood moved along the veins?
By the contraction and relaxation of the skeletal muscle surrounding them
What kind of walls do each of the blood vessels have?
Artery: Thick, muscular, elastic
Vein: Not thick, not muscular, less elastic tissue
Capillary: One cell thick
What kind of lumen do each of the blood vessels have?
Artery: Small
Vein: Large
Capillary: Very small
Do all the blood vessels have valves?
Artery: No valves
Veins: Valves
Capillary: No valves
What is the direction of flow of blood for each blood vessel?
Artery: Carries blood away from heart
Vein: Carries blood towards the heart
Capillary: Carries blood from arterioles to venules
What is the blood flow like in each blood vessel?
Artery: Blood flow fast, high pressure
Vein: Blood flow slow, low pressure
Capillary: Blood flow slow, pressure decreases from arterioles to venules
What are the arteries that leave the heart?
1) Pulmonary artery from the right ventricle to the lungs
2) Aorta from the left ventricle
What are the arteries that arise from the aorta?
1) Arteries to the head, neck and arms
2) Hepatic artery to the liver
3) Artery to the stomach and intestines
4) One renal artery to each kidney
5) Artery to the hind limbs
What are the veins returning to the heart?
1) Pulmonary veins from the lungs to left atrium
2) Superior vena cava and inferior vena cava to the right atrium
What are the veins that merge with the superior and inferior vena cava?
Superior vena cava:
1) Veins from the head, neck and arms
Inferior vena cava:
1) Renal vein from the kidneys
2) Hepatic vein from the liver
3) Hepatic portal vein from the stomach and small intestines to the liver
4) A vein from the hind limbs
Why can red blood cells pass through the capillaries one at a time only?
The capillary lumen is very small and narrow. However, red blood cells can change into bell-shaped when they move through the lumen
What are the advantages of red blood cells becoming a bell-shape when moving through the capillary lumen?
1) They can move through the lumen easier because of the decrease in diameter
2) They speed up the release of oxygen due to an increase of the surface area to volume ratio
How many times does blood pass through the heart in one complete cycle?
Twice (double circulation)
What are the 2 circulations?
1) Pulmonary circulation: From the heart, pulmonary arteries carry blood to lungs and pulmonary veins bring blood back to the heart from the lungs
2) Systemic circulation:
Blood leaves the heart and is distributed by arteries to the rest of the body and veins carry blood back from the body to the heart
What is the median septum?
The median septum is a dividing wall in the middle of the heart that separates the heart into the right and left sides
What happens if there is no median septum and the deoxygenated and oxygenated blood mix?
The mixing of the 2 types of blood can cause a decrease in the amount of oxygen carried to the body. So the median septum serves serves the purpose of completely separating the two sides to prevent the possibility of mixing between both bloods
What happens if there is a hole in the median septum?
Blood can flow from the left side of the heart mostly to the right side through the hole because the pressure in the left side is higher than the right side. This causes mixing of oxygenated and deoxygenated blood, reducing the amount of oxygen being transported to the body cells for respiration, resulting in shortness of breath, fatigue or heart failure
What are the four chambers in the heart?
Right atrium, right ventricle, left atrium, left ventricle
What valves are present in the heart?
The right atrium has a tricuspid valve and the left atrium has a bicuspid valve, both have semi lunar valves
What is the function of a valve?
Valves prevent backflow of blood
When do valves open and close?
Valves open during contraction of the chamber and closes when the chamber relaxes
Where does tricuspid valve prevent backflow of blood from?
From the right ventricle to the right atrium
Where does bicuspid valve prevent backflow of blood from?
From the left ventricle to the left atrium
Where do the semi lunar valves prevent backflow of blood from?
Right side: Pulmonary artery to right ventricle
Left side: Aorta to left ventricle
Do the atria or the ventricles have thinner walls and why?
The atria has thinner walls because the walls only force blood into the ventricles that lie directly below them so they do not require thick, muscular walls (for high pressure). However, the walls of the ventricles need to be muscular to push the blood to the lungs and rest of the body (for high pressure)
Which ventricle has thicker walls and why?
The left ventricle has thicker walls than the right ventricle because it requires a higher pressure to exert enough force to pump the blood to the rest of the body. However, the right ventricle only pumps blood to the lungs, which is closer to the heart so it doesn’t require the same amount of pressure
Describe the path of blood flow from the vena cavae to the heart
1) Deoxygenated blood returns from the body to the right atrium via the van cavae (superior from head neck and arms, inferior from rest of the body)
Describe the path of blood flow from the right atrium to the right ventricle
2) Deoxygenated blood flows from the right atrium into the right ventricle by the tricuspid valve (the chordae tendineae attach the flaps to the walls of the right ventricle to prevent them from reverting into the right atrium during ventricular contraction)
Describe the path of blood flow from the right ventricle into the pulmonary artery
3) Deoxygenated blood flows from the right ventricle into the pulmonary artery through the semi lunar valve
Describe the path of blood flow after blood reaches the pulmonary artery
4) Deoxygenated blood flows from pulmonary artery to the lungs
Describe the path of blood flow from the lungs to the heart
5) Oxygenated blood returns from the lungs to the left atrium by the pulmonary vein
Describe the path of blood flow from the left atrium to the left ventricle
6) Oxygenated blood flows from the left atrium into the left ventricle through the bicuspid valve (the chordae tendineae attach the flaps to the walls of the left ventricle to prevent them from reverting into the right atrium during ventricular contraction)
Describe the path of blood flow from the left ventricle to the aorta
7) Oxygenated blood flows from the left ventricle to the aorta through the semi lunar valve
Describe the path of blood flow after blood reaches the aorta
8) Oxygenated blood flows from the aorta to the rest of the body through different arteries (there are 2 small coronary arteries branching out from the aorta to supply oxygen and nutrients to the heart muscles)
What is the cardiac cycle and what does it involve?
The series of events that takes place in one heart beat. It involves the contraction of atrial or ventricular muscles (systole) and the relaxation of atrial and ventricular muscles (diastole)
What happens at the start of the cardiac cycle?
1) Both the atrial and ventricular muscles relax and the bicuspid and tricuspid valves open, allowing blood flow from the atria into the ventricles
What triggers the atrial systole phase?
2) The atrial muscles contract to complete the filling of blood in the ventricles
What happens immediately after atrial systole?
3) The ventricular muscles contract and pressure in rises causing the bicuspid and tricuspid valves to close to prevent backflow of blood into the atria
What happens to the ventricular pressure after the ventricular muscles contract?
4) The pressure in ventricles become higher than the pulmonary artery and aorta and the semi lunar valves open causing blood to be forced out from the right ventricle and left ventricle into the pulmonary artery and aorta respectively
What happens to the atrial muscles after the ventricular muscles contract?
5) The atrial muscles start to relax, and the right atrium collects blood from the pulmonary vein
What happens after blood is pumped out of the heart?
6) The ventricular muscles start to relax, the pressure in the ventricles falls, causing the semi lunar valves to close to prevent backflow of blood into the ventricle from the arteries
What happens to the pressure in the ventricles after ventricular diastole?
7) When pressure in the ventricles is lower than the atria, the bicuspid and tricuspid valves allow blood to flow form the atria to the ventricles. Both atrial and ventricular muscles relax and the cycle repeats
The atria and ventricles work ____
Alternately, when atrial muscles contract, ventricular muscles relax (vice versa)
What is one heart beat made up of?
A ventricular systole and a ventricular diastole
What is the average normal heart beat of an adult?
72 beats per minute
How do we obtain the number of heartbeats per minute?
By counting the number of pulse beats per minute
Where does the heart receive blood from?
2 main coronary arteries (receives 4-5% of the blood output of the heart)
What would happen if any of the coronary arteries were blocked
Blood supply will reduce and that muscle will not receive sufficient oxygen and nutrients causing the death of that muscle and the heart could stop pumping blood to the rest of the body (this could cause chest pain or even die). If a CA is completely blocked, heart attack occurs
What is the main cause of coronary heart disease?
Atherosclerosis which is the build up of fatty substances deposited in the inner surface of the coronary artery. This increases the chance of blood clots being trapped in the narrow lumen. Blood and oxygen to the heart muscles may be cut off. When no oxygen is supplied to the muscles for respiration, they may become damaged and cause a heart attack
What are the factors that increase the risk of atherosclerosis?
1) Unhealthy diet (rich in cholesterol and saturated animal fats)
2) Age
3) Smoking
4) Genes
5) Sedentary lifestyle
What are some preventative measures of coronary heart disease?
1) Healthy diet (low saturated animal fats)
2) Regular exercise
3) Avoid smoking
