Human circulatory system Flashcards
What does plasma play a role in transporting
- Respiratory gases
- Nutrients
- Metabolic waste
- Hormones
- Heat
What are red blood cells also known as
Erythrocytes
What are the adaptations of red blood cells
- Presence of haemoglobin allows oxygen to be transported around the body
- Biconcave shape increases SA:V for faster rate of diffusion of gases
- Absence of nucleus allows more haemoglobin to be packed in the cell, so more oxygen can be carried
- Elastic so it can squeeze through blood vessels smaller than itself
How does plasma maintain homeostasis of body
- Maintains optimum pH of blood using buffers
- Maintains water potential of blood
- Maintains temperature of blood
What are white blood cells also known as
Leucocytes
What are the 2 types of white blood cells
- Phagocytes
- Lymphocytes
What is the structure and function of phagocytes
- Irregular shape
- Lobed nucleus
- Engulfs and ingests foreign particles like bacteria by phagocytosis
- Phagocytes killed with bacteria forms pus
What is the structure and function of lymphocytes
- Round
- Large nucleus
- Produce antibodies that neutralise toxin produced by bacteria
- Produce antibodies that cause agglutination, where bacteria clump together and attract phagocytes to engulf and ingest clumped bacteria
What are platelets also known as
Thrombocytes
Describe the mechanism of blood clotting
- When blood vessels are damaged, damaged tissue and platelets produce thrombokinase
- Thrombokinase converts prothrombin to thrombin
- Thrombin converts soluble fibrinogen into insoluble fibrin threads
- Insoluble fibrin threads trap blood cells and the whole mass forms a scab or clot
- Undamaged blood vessels contain heparin which is an anti-clotting substance
- Released thrombokinase also neutralises heparin so clotting can occur
What antigens and antibodies does blood group O have
- No antigens
- Anti-A and Anti-B antibodies
What antigens and antibodies does blood group A have
- Antigen A
- Anti-B antibody
What antigens and antibodies does blood group B have
- Antigen B
- Anti-A antibody
Can A be donated to O
No
Can B be donated to AB
Yes
What antigens and antibodies does blood group AB have
- Antigen A and Antigen B
- No antibodies
Can AB be donated to B
No
Can O be donated to A
Yes
Why is blood type O the universal donor
- No antigens
- Recipient’s antibodies would not cause agglutination of donor’s blood
Why is blood type AB the universal acceptor
- No antibodies
- Donor’s antigens will not cause agglutination
What is a transfusion
A transfusion is the transfer of whole blood or blood components into bloodstream of another person
What is agglutination
Agglutination is the binding of antibodies in recipient’s plasma to antigens on donated red blood cells
Why is agglutination dangerous
- Red blood cells become cross-linked to another
- Immune system ruptures the red blood cells
- Released haemoglobin may cause kidney damage
Why is the reaction between donor’s antibodies and recipient’s antigens not significant
Donor’s antibodies are diluted in recipient’s plasma
Describe double circulation and its advantages in mammals
1) Double circulation completely separates oxygenated and deoxygenated blood
- Ensures that only oxygenated blood reach cells
- Ensures efficiency of oxygen transport
2) Blood goes through pulmonary circulation at low pressure
- Ensures that blood flows slowly through the lungs to allow for sufficient time for diffusion of gases
3) Blood goes through systemic circulation at high pressure
- Ensures that oxygenated blood can be transported quickly, maintaining high metabolic rate in mammals
Where do arteries carry blood to
Away from heart
Why does blood pressure fall along capillaries from arteriole end to venule end
Increase in total cross-sectional area
Where do veins carry blood to
Towards heart
What are the adaptations and functions of arteries
- Thick, muscular arterial walls can withstand high pressure from contraction of ventricles, allowing blood to be transported quickly
- Elastic tissue in arterial walls enables arteries to stretch and recoil under pressure, helping to push blood along in spurts
- Muscular tissue in arterial walls allow for constriction and dilation to regulate volume of blood flow
What are the adaptations and functions of capillaries
- One-cell thick wall allows substances to diffuse through capillary walls quickly
- Presence of intercellular clefts increase rate of diffusion of substances
- Extensive network of capillaries around cells enables efficient exchange of materials
What are the adaptations and functions of veins
- Large lumen decreases resistance to blood flow, so blood can flow back to heart smoothly
- Presence of semi-lunar valves prevent the backflow of blood under low blood pressure to ensure blood flows in one direction
How do skeletal muscles help in blood flow
- Skeletal muscles next to veins compress the veins when muscles contract
- This helps push blood towards the heart and slows down blood flow
Describe the transfer of materials between capillaries and tissue fluid
- Tissue and cells are surrounded by tissue fluid, which fills intercellular spaces and acts as a medium for materials to diffuse between blood and cells
- Nutrients present in blood diffuse through tissue fluid and into cells
- Wate products diffuse through tissue fluid from cells into blood
Describe atrial systole
- Atria contract to force remaining blood through bicuspid or tricuspid valves into ventricles
Describe blood flow from once it enters the heart to once it leaves the heart
- From body, enters heart from vena cava and goes into right atrium
- Goes to right ventricle after passing through tricuspid valves
- Goes to pulmonary artery after passing through semi-lunar valves
- Goes to lungs
- From lungs, enters heart from pulmonary veins and goes into left atrium
- Goes to left ventricle after passing through bicuspid valves
- Goes to aorta after passing though semi-lunar valves
- Goes to body
Describe ventricular diastole
- Ventricles relax, ventricular pressure decreases
- Results in the backflow of blood from aorta or pulmonary artery
- Blood flows backwards, forcing the semi-lunar valves shut, producing a ‘dub’ sound
- Bicuspid or tricuspid valves open once ventricular pressure is lower than atrial pressure, allowing blood to flow into ventricles
Describe atrial diastole
- Occurs at same time as ventricular systole
- Atria relax so blood from pulmonary veins or vena cava start filling up the atria
Describe ventricular systole
- Ventricles contract, ventricular pressure increases
- Pressure pushes the bicuspid or tricuspid valves upwards and forcing them shut, producing a ‘lub’ sound
- Semi-lunar valves open once ventricular pressure is higher than aortic pressure or pulmonary artery pressure
- Blood enters aorta or pulmonary artery from ventricles
Define blood pressure
Blood pressure is the force that blood exerts on the walls of blood vessels
What is atherosclerosis
Atherosclerosis is a condition where cholesterol and fatty deposits accumulate on inner walls of coronary arteries
What are coronary arteries
Arteries that branch out from the aorta to provide oxygen and nutrients to heart muscles
What is angina
Chest pain or discomfort in region of heart that does not receive sufficient blood
What factors increase the risk of getting a heart attack
- Being a male
- Family history
- Age
- Smoker
- High intake of saturated fats, salt, alcohol, sugar
- Lack of exercise
- High blood pressure
What are the treatment methods of coronary heart disease
- Balloon angioplasty
- Coronary artery bypass grafting
