HCS Flashcards
What are the functions of blood
Transport medium for red blood cells, white blood cells, nutrients and waste materials
Protection against pathogens
Protection against loss of blood through blood clotting
Regulate body temperature, pH, water content of cells
What is plasma made up of
90% water
10% proteins and other dissolved substances
Function of plasma
Transport water, proteins, dissolved substances, platelets, and blood cells around the body
How does a biconcave shape help a red blood cell
Increases surface area to volume ratio -> increases rate of diffusion of oxygen
How does an absence of nucleus help a red blood cell
Allows more haemoglobin to be packed -> transport more oxygen
State 3 characteristics of white blood cells
- Circular/oval/irregular shape
- Contains nucleus
- Some able to move, change its shape or squeeze through narrow capillaries
Function of white blood cells
- Produce antibodies that identify and neutralize pathogens
- Engulf pathogens
What are platelets
Membrane bound fragments of cytoplasm from the bone marrow
Why are platelets not true cells
No nucleus
What to platelets contain
Clotting factors and enzymes to help blood clotting
What is the function of platelets
Involved in the process of blood clotting which is crucial in preventing excessive bleeding
Function of artery
Transport blood away from the heart
Function of veins
Transport blood towards heart
Function of capillaries
Allow exchange of oxygen, carbon dioxide, nutrients and waste products between tissue fluid and blood by diffusion
Thickness of artery walls
Thick, muscular walls with smaller lumen relative to diameter
Thickness of vein walls
Thin, muscular walls with larger lumen relative to diameter
Thickness of capillary walls
One-cell thick walls
Why do capillary walls have such a thickness
Reduce the distance over which diffusion occurs to increase rate of diffusion
Why is the rate of blood flow in capillaries slow
To allow diffusion to take place effectively
How does the circulatory system pump blood from the feet to the heart against gravity
Contraction of skeletal muscles compressing the veins
What is the role of tissue fluid
Allow diffusion of oxygen and glucose from capillaries to cells and diffusion of carbon dioxide and waste products from cells to capillaries
What process do heart muscles go through to get energy and why do heart muscles need energy
Get energy from oxygen and glucose through respiration
Need energy for contraction
Where do heart muscles get their supply of oxygen and glucose
Coronary arteries that branch off aorta supply heart with oxygenated blood and glucose
What does an unhealthy lifestyle cause
Build-up of fatty deposits along the walls of coronary arteries -> narrows lumen -> reduces blood supply -> block coronary artery significantly -> heart starved of oxygen and glucose -> tissue death -> heart attack
Why is it when one survives a heart attack their heart still beats faster than before
Rest of healthy heart muscles need to pump blood faster to compensate for damaged heart muscle
Risk factors of Coronary Heart Disease
Poor diet: diet high in fats and cholesterol
Poor lifestyle: smoking, lack of exercise, stress
Genetic factors: family history of heart disease
