Mass Tranport In Humans Flashcards
Systole
Contraction of heart muscle
Diastole
Heart muscle relaxed
3 stages of cardiac cycle
Atrial systole
Ventricular systole
Diastole
Cardiac cycle process
- Deoxygenated blood returns from the body in the vena cava and enters the right atrium. Lower volume increases pressure in atrium. Pressure in atrium is greater than ventricle which causes atrio ventricular valve to open. Blood passes into the right ventricle. Atrium muscles contract as further increases pressure and remaining blood forced into ventricle from atrium
- Blood enters ventricle increases pressure and ventricle due to volume of blood pressure in ventricle greater than an atrium at ventricular valve closes
- Ventricle muscles contract as further increase pressure in ventricle and greater than in pulmonary artery. Semilunar valve opened blood enters the pulmonary artery and pumped to the lungs
- Ventricle muscles relax as pressure in ventricle is less than in a water semilunar valve closes. Blood enters the atrium and blood volume increases back in atrium.
- Blood enters into pulmonary vein into left atrium to left ventricle then out the aorta
Pressure changes in a graph
Cardiac output definition
The volume of blood pumped out of the left ventricle per minute
Equation for cardiac output
CO = SV X HR
Dm3min-1
What are the coronary arteries?
Deliver oxygenated blood and glucose to the heart muscle itself
Two most common causes of blockage to the coronary arteries
- Atherosclerosis= damage to endothelium wall and process of narrowing or blocking of arteries
- Thrombosis= plaque build up from smoking or other factors which may rupture and trigger blood platelets to form a blood clot which further blocks the artery
- Aneurysm = blockage of artery which causes high pressure of blood and causes wall to weaken and start to bulge out. This vessel may rupture and result in internal bleeding
Risk factors in coronary heart disease
Age
Gender = Men are out more risk than women as protective effect of oestrogen
Genetic factors = Same family may have similar lifestyles
Smoking = Nicotine increases blood pressure, therefore damage to the endothelium wall, Also increases level of cholesterol in blood
Stress = Increased blood pressure therefore damage to the endothelium cell wall
High lipid or cholesterol diet
Kidney
Important for excretion of waste and maintaining correct water potential in blood two vessels associated with the kidney
Renal artery and vein which take blood to and away from the kidney
Artery
Take blood away
Vein
Take blood into
Label the heart
Heart to lungs to kidney to heart
Artery structure and function
Artery = carries blood away from the heart at high pressure
- Thick muscle layer which contracts and relaxes. When it contracts, it becomes smaller which means it allows high blood pressure to pass through/ increase blood pressure
- Thick elastic layer which stretches and recoil. When it stretches it allows greater volume of blood to pass through the arteries
- Smooth inner lining layer= reduces fiction
- Thick wall made of fibrous protein which helps it withstand great pressure
- Narrow lumen = Maintains high blood pressure
Arteriole structure and function
- Arteriole= smaller arteries which connect to the capillaries and provides oxygen to cells closer to the artery
- Thicker smooth muscle layer = contracts and relaxes, when it contracts it makes the lumen smaller and reduces blood flow to the capillaries so cells can take oxygen needed from the capillaries instead of blood flowing to quick
- Thinner elastic layer which stretches and recoils= pressure surges is low way from heart so not needed
Veins structure and function
- Veins = carry blood into the heart at lower pressure
- Wide lumen= less resistance to blood flow
- Little elastic and muscle layer = low blood pesssure
- Valves which prevent backflow as boood pressure is low and blood gluing against gravity
Capillaries structure and function
- Capillaries= allow efficient gas exchange of substances between blood and respiring cells
( link to ficks law) - Thin wall which is one cell thick = reduces diffusion distance
- Branched = increase surface area for diffusion
- Narrow lumen = reduces blood flow
- Pores called festrations = which allow larger substances to pass into and out the capillaries
What is tissue fluid
Cells in the tissue have numerous spaces around them and this is filled with tissue fluid. The fluid is formed from blood plasma which is made from dissolved gasses ans nutrients.
Materials pass from the plasma into the tissue fluid and into the tissue fluid into the cells
Formation of tissue fluid
- High blood hydrostatic pressure inside the capillaries than the oncotic pressure of the tissue fluid.
- Forces water / fluid out;
- Large proteins remain in capillary;
Return of tissue fluid
Lower water potential in capillary / blood;
5. Due to (plasma) proteins;
6. Water enters capillary (venous end) / blood;
7. (By) osmosis;
8. Correct reference to lymph;
Gas exchange in humans
- Oxygen goes from the mouth in to the trachea which are made of rings of cartilage to prevent it from collapsing
- The trachea splits into 2 called the bronchi and oxygen either go to the left or right bronchi
- The bronchi then splits into further branches called bronchioles which are increase surface area abd supply the alveoli with air
- There are many alveoli’s which means increased surface area, 1 cell thick so short diffusion distance and maintain a large concentration gradient between gasses in blood and alveoli
- Alveoli air is separated from blood into the first layer called alveoli epithelium which is one cell thick
- Then air goes into the second layer called the capillary endothelium then into the blood where the red blood cells transport it to respiring cells to produce ATP
What is ventilation
Process of breathing
Inhalation = breathing in
- External intercostal muscles contract and pull the rib cage up and out
- The diaphragm contracts and pull down
- Thoracic cavity volume increases
- Pressure in lungs in lower than atmospheric pressure
- Air moves into the lungs down a pressure gradient
Exhalation =breathing out
- External intercostal muscles relax
- Diaphragm relaxes and moves up
- Theoretic cavity volume decreases
- Pressure in lungs is greater than atmospheric pressure
- Air moves out of the lungs down a pressure gradient
