chpt 6 transport in humans Flashcards
1
Q
What is the blood system ?
A
1.blood system is a double circulation consisting of the systematic circulation and pulmonary ciculation
2. systematic circulation -> oxygenated blood transported from heart to body and transports deoxygenated blood back to heart
3. pulmonary circulation -> deoxygenated blood pumped from heart to lungs, returns oxygenated blood back to heart
2
Q
What is the lymphatic system ?
A
- one way system from the interstitial fluid to the cardiovascular system
3
Q
How does the rbcs transport oxygen ?
A
- blood passes through lungs of high oxygen conc, oxygen diffuses from alveoli into the rbcs
- haemoglobin combines reversibly with oxygen to form oxyhaemoglobin
- as blood passes through the tissues in the body
- oxyhaemoglobin releases the oxygen in places of low oxygen conc
4
Q
What is the process of blood clotting ?
A
- blood platelets release enzyme called thrombin
- thrombin catalyses conversion where soluble protein fibrinogen converts to insoluble fibrin threads
- insoluble fibrin threads then entangle blood cells and forms the whole mass known as a clot or a scab
5
Q
What blood do arteries, vein and capillaries transport ?
A
artery except pulmonary arteries transport oxygenated blood away from heart
veins except pulmonary veins transport deoxygenated blood to heart
arteries - arterioles - capillaries - venules (acts as branches and links capillaries together) - veins
6
Q
What are the features of an artery ?
A
- branches out into arterioles and eventually capillaries
- blood moves under high pressure and in pulses
- thicker, muscular wall for constriction and dilation of artery
constriction -> lumen narrower, less blood flows through it per unit time
dilation -> lumen wider, more blood flows through it per unit time - elastic walls
helps to withstand high pressure from ventricular contractions of the heart
allows stretching and recoiling of artery wall, helps to push blood and give rise to the pulse
7
Q
What are the features of a vein ?
A
- venules join together to form veins (carry deoxygenated blood back to heart)
- blood moves under low pressure
- less muscular and elastic, but has a bigger lumen than arteries
blood flows more slowly and smoothly - presence of semi lunar valves to prevent backflow of blood
- surrounded by skeletal muscles
mvment of blood in veins is aided by actions of skeletal muscles on veins
muscle contractions exert pressure on veins and pushes blood back to heart
8
Q
What are the features of capillaries ?
A
- microscopic blood vessels found btwn cells of almost every tissue
- wall is made up of single layer of cells called endothelium cells (enables faster mvment of substances)
- partially permeable endothelium wall -> enables smaller substances eg glucose and oxygen to quickly diffuse through
- capillary networks are highly branched
provides large surface area for site of exchange of substances btwn blood and tissue cells
when arterioles branches into capillaries, lowers blood pressure and speed so exchange of substances has more time to occur
9
Q
What is in the tissue fluid ?
A
- glucose, amino acids (dissolved foods) and oxygen diffuses from capillaries into tissue fluid ad then into cells
- waste products and co2 diffuse from cells into tissue fluid and into capillaries
- tissue fluid is returned to the capillary system through lymphatic capillaries
- if tissue fluid is not returned to body, it will cause accumulation and swelling of tissues and organs in the body (oedema)
10
Q
What paths does blood take to the heart ?
A
- deoxygenated blood returned to right atrium through venae cavae
- right atrium contracts to push blood into right ventricle
- blood leaves heart through pulmonary arteries to the lungs
- oxygenated blood is returned back to the heart through the pulmonary veins into the right atrium
5.right atrium contracts to pump blood into right ventricle - left ventricle contracts and pumps oxygenated blood to rest of body through the aorta
11
Q
Describe stage 1 diastole.
A
- resting period of all heart chambers
- all muscles relaxed and blood flow into heart
- bicuspid and tricuspid valves open when pressure in atria is more than pressure in ventricles to allow passive flow of blood to the ventricles
- oxygenated blood enters left atrium deoxygenated blood enter right atrium
12
Q
Describe stage 2 atrial systole.
A
- muscles of atria contract, but muscles of ventricles remain relaxed
- bicuspid and tricuspid valves fully opened to allow passive flow of blood into the ventricles
- semi lunar valves remain closed
13
Q
Describe stage 3 ventricular systole.
A
- muscles of ventricles contract while muscles of atria relax
- steep increase of pressure in ventricles forcefully closes bicuspid ad tricuspid valves, producing first “lub” sound in heart
- ventricles pressure more than pressure in atria, forces semi lunar valves open
- blood forced from the heart into the pulmonary arteries (deoxygenated blood from right ventricle to heart) and the aorta (oxygenated blood from the left ventricle)
14
Q
Describe stage 1 ventricular systole.
A
- as ventricles start to relax, pressure within them falls
- high pressure in aorta and pulmonary arteries tend to result in some blood flowing back into the ventricles
- this closes semi lunar valves to prevent backflow of blood
- impact of backflow of blood against the semilunar valves forms second softer “dub” sound
- two sides of heart are separated by the median septum to prevent mixing of blood
15
Q
What are the coronary arteries ?
A
- two small coronary arteries emerge from the aorta and runs on the outside of the heart
- function of the coronary arteries is to supply oxygen and nutrients to the cardiac muscles
