Biology Flashcards
What is the function of the pulmonary circulatory system?
Carry blood from the heart to the lungs & back
What is the function of the systemic circulatory system?
Carry blood from the heart to the body & back
What is the function of the coronary arteries?
Deliver oxygenated blood to the heart muscle
Describe the structure of arteries
Thick muscular layer Narrow lumen Thick elastic layer Blood travels at high pressure
Describe the structure of veins
Thin muscular layer Wide lumen Thin elastic layer Blood travels at low pressure Has valves
What is the structure that divides the heart into left and right sides called?
Septum
Where are the semi-lunar valves located?
At the bottom of the arteries heaving the heart
What is the function of valves?
Prevent backflow
What does myogenic mean?
Can generate electrical impulses without input from the brain
Where is the SA node located?
In the wall of the right atrium
Describe the structure of heart muscle.
Striated Resembles skeletal muscle but the fibres are less wide Joined at intercalated discs for quick transmission of impulses
What ions do cardiac muscle cells need to contract?
Calcium ions
What is the function of the SA node?
The heart’s pacemaker. it generates impulses to cause contraction of heart muscles.
What is the average heart rate?
70-80 bpm
What is the function of the AV node?
Slows down the impulses to allow ventricles to fill before contracting.
What are the Bundles of His?
Specialised muscle fibres that conduct electricity
Why must ventricular contraction start at the apex of the heart?
To prevent blood from being trapped at the bottom of the ventricles.
What is the equation to calculate cardiac output?
Cardiac output = stroke volume x heart rate
Where are antigens located?
On the surface of red blood cells
Where are antibodies located?
In the blood plasma
What blood type is called the universal donor?
O negative
What blood type is called the universal recipient?
AB positive
What factors increase the risk of CVD?
Genetics Age Gender Diet High blood pressure Smoking Inactivity
How can CVD be treated?
Antihypertensives Statins Transplantation and immunosuppressants
How are the lungs adapted for efficient gas exchange?
Short diffusion pathway Large surface area Maintenance of diffusion gradients
What is the residual volume?
The volume of air that remains in the lungs after the deepest exhale.
What is the tidal volume?
The volume of air inhaled/exhaled in a normal breath
What is the inspiratory reserve volume?
The volume of air that can be inhaled after a normal inhalation.
What is the expiratory reserve volume?
The volume of air that can be exhaled after a normal breath out.
What is the vital capacity?
The volume of air that can be exhaled after the the deepest breath in.
What is peak expiratory flow rate?
The maximum speed of expiration
What is a peak flow meter for?
Measuring the ability to breathe out air and can monitor degree of obstruction in airways. They can be used to determine lung function in asthma and emphysema patients.
What is forced vital capacity?
The amount of air that can be forcibly exhaled after a deep breath in.
What is forced vital capacity used to determine?
The presence and severity of lung disease.
How does exercise affect oxygen consumption?
Increases it.
What is respiratory minute ventilation?
The volume of air passing into and out of the lungs per minute.
What is the equation for respiratory minute ventilation?
RMV = tidal volume x breathing rate
What is excretion?
The removal of toxic metabolic waste.
What is osmoregulation?
The regulation of the concentration of solutes in body fluids, by regulating salt and water in the body
What is the function of the ureter?
Carry urine from the kidneys to the bladder.
What is the function of the bladder?
Stores urine prior to removal.
What is the function of the renal artery?
Supplies blood to the kidney.
What is the function of the renal vein?
Carries blood away from the kidney.
Where does ultrafiltration occur?
Glomerulus & Bowman’s capule
What is the role of the proximal convoluted tubule?
Reabsorb most of the filtrate: water, glucose, ions
What is the role of the loop of Henle?
Set up an area of high concentration in the renal medulla, which the collecting duct passes through.
What is the role of the distal convoluted tubule?
Help to control blood pH by adding or removing hydrogen ions, helpts to control blood volume and concentration of urine by absorbing ions into blood (caused by aldosterone)
Why does water get reabsorbed in the collecting duct?
It passes through an area of high concentration, therefore water is reabsorbed back into the blood by osmosis
What hormone controls the reabsorption of water?
ADH
What is the role of ADH?
It is released when blood concentration is too high. It causes the collecting duct to become more permeable and therefore more water is reabsorbed.
What hormones are produced when blood pressure is low?
Angiotensinogen –> angiotensin I – > angiotensin II
How does angiotensin II afftect the kidneys?
It stimulates the production of aldosterone, causing more sodium to be retained by the kidneys.
What does the fluid mosaic model contain?
- phospholipid bilayer
- extrinsic and intrinsic proteins
- cholesterol
- protein channels
- protein carriers
- antigens and receptors
What is facillitated diffusion?
Ions and molecules that would not be able to cross the cell membrane are able to cross using protein channels or carrier proteins
What is endocytosis?
Vesicles are formed from cell membrane to engluf large substances into the cell. It is a form of active transport.
What is exocytosis?
Vesicles inside the cell join with the cell membrane to release large molecules. It is a form of active transport.
What happens to the surface area to volume ratio (SA/V) when the size of an organism increases?
SA/V decreases
What is a statin?
A type of medication used to lower the cholesterol levels in the blood.
What are the risks of statins?
dizziness
risk of liver or kidney damage
What are the benefits of statins?
reduces the risk of narrowed arteries
helps fight inflammation
What are some examples of high blood pressure medications?
diuretics
beta blockers
What are the pros of high blood pressure tablets?
Wide range of medications so a suitable option can be found for each individual
What are the cons of high blood pressure medication?
erection problems
weakness/ fatigue
insomnia
Describe the cardiac electrical conducting system
stage 1: impulse generated through the sinoatrial node and into the atria
stage 2: impulse generated at the atrioventricular node allows for the electrical imule to slow down
stage 3: impulse generated down the bundle of His through the ventricular walls and up the purkinje fibres
stage 4:no impulse
Describe the cardiac cycle
Stage 1: atria contracts ventricles relax
ventricles fill with blood through the AV valve
articular systole ventricular diastole
Stage 2: atria contracts ventricles relax
blood is slowly pushed through the AV valve
ventricular diastole and articular systole
Stage 3:
ventricles contract and atria relax
semilunar valves open
blood is pushed through the pulmonary artery
ventricular systole articular diastole
Stage 4;
ventricle and atria relax
Passive filling
Ventricular and auricular diastole
What is surfactant?
Substance in the lungs that keeps the lungs open and prevents the lungs from collapsing by lowering surface tension
