Module 8 Flashcards
what is homeostasis
Homeostasis is the maintenance of a stable internal metabolic environment (set point). This is necessary for optimal enzyme function
3 types of neurones?
Sensory neurones detect stimuli such as pain, pressure, temperature, taste, sound, sight, smell etc. using receptors at the ends. They store their nuclei in cell bodies attached to the side of the axon.
Motor neurones are responsible for moving; they send electrical impulses to electors (mainly muscles) to carry out voluntary and involuntary action so
Relay neurons (a.k.a. connector neurones, interneurons) carry information between motor and sensory neurons, and make up the spinal cord and brain
type of sensory
Chemoreceptors detect the presence of chemicals.
Thermo receptors detect changes in temperature.
Mechanoreceptors detect mechanical forces.
Photoreceptors detect light during vision.
pancreas role
The pancreas is one of the most important organs of homeostasis as it controls blood glucose. It contains two types of endocrine cells – alpha cells (which produce glycogen)and beta cells (which produce insulin)
what is negative feedback
Negative feedback is where the body recognises that it is not at set point and corrects the imbalance in the opposite
what is positive feedback
Positive feedback is where the stimulus is reinforced and leads to an amplified response, e.g. labour during childbirth,
what happens when BGL are to high
cells in the pancreas release insulin, causing the body to absorb glucose, from the blood, the liver turning it to glycogen and stores it and lowering the blood sugar level to normal.
what happens when BGL are to low
- alpha cells in pancreases release glucagen
- liver breaks down glyogen to glucose
- bgl increases
plants water balance
-Plants in hot climates thus have a wide variety of structural and physiological adaptations to prevent excess water loss
deep root systems, thin needle-like, curled, or vertically hanging leaves with thick waxy cuticles, sunken stomata with stomatal hairs which only open in the morning, hard fruit and small flowers, water storage in trunks, and loss of leaves/limbs in very dry periods
Mechanisms and Adaptations
Structural adaptations such as ear size, fur, etc. (anatomical), physiological adaptations such as hibernation, sweating etc. (metabolic), and behavioural adaptations such as burrowing
eh artic foxes
Outline the function of the Cochlea (snail)
-> filled with a fluid that moves in response to the vibrations from the oval window.
fluid moves= 25,000 nerve endings are set into motion= transform the vibrations into electrical impulses = travel along the eighth cranial nerve (auditory nerve) to the brain.
outline the function of the organ of the corti (hearing)
three rows of outer hair cells and one row of inner hair cells
Vibrations caused by sound waves bend the stereocilia on these hair cells via an electromechanical force.
outline 2 types of hearing loss
- Conductive hearing loss
- Sensorineural hearing loss
outline conductive hearing loss
caused by a problem with the mechanical conduction of vibrations
through the outer and middle ear
could be from trauma
outline Sensorineural hearing loss
- permanent
- caused by damage to, or malformation of, the inner ear, including parts
of the cochlea, the hair cells or the auditory nerve. - from excessive noise exposure, heredity, birth defects, infections, tumours,
medication and ageing.
name 3 technologies for hearing loss
- hearing aids
- bone conduction implant
- cochlear implant
name 3 technologies for hearing loss
- hearing aids
- bone conduction implant
- cochlear implant
what does hearing aids do
magnify the sound vibrations to better enable their transmission to the
middle ear and then the inner ear.
for conductive
what does hearing aids do
magnify the sound vibrations to better enable their transmission to the
middle ear and then the inner ear.
for conductive
what does bone conduction implant do
Microphone that detects the sound and transforms it into
Vibrations - there is a risk of infection and inflammation at the implant site after surgery.
what does cochlear implant do
external speech processor and transmitter coil - conversion of sound into electrical impulses that stimulate an
electrode array implanted in the cochlea, which in turn stimulates electrochemical impulses in
the auditory nerve.
outline processes of eye focussing light
- light passes through the cornea
- convex nature of the cornea bends the light
- enters pupil
- light passes through the lens. The lens works together with the cornea to focus light correctly on the retina.
- light hits the retina, photoreceptors turn the light into electrical signals.
- electrical signals travel from the retina through the optic nerve to the brain
outline the role of rods
are evenly distributed over most of the retina,
→ Contain “rhodopsin” = extremely sensitive to low levels of light = responsible for vision at low light levels
outline role of cones
contain 3 pigments = light of one particular wavelength may stimulate more than one type of cone. By comparing the rate at which various receptors respond, the brain is able to interpret these signals as intermediate COLOURS
name three vision disorders
- hyperopia (longsighted)
- Myopia (short sighted)
- astigmatism (cornea or the lens has mismatched curves)
what does hyperopia need in terms of lens shape
Convex (to bend the light in)
what does myopia need in terms of lens shape
concave (to bend light outwards)
what is the cause of hyperopia
→ The eyeball is too rounded
→ lens is too flat and is unable to achieve the required convexity.
what is the cause of myopia
→ shape of the eyeball may be too elongated.
→ lens may not flatten enough when the ciliary muscles contract
outline 3 technologies for vision disorders
- Spectacles
- Lasik
- Cataract surgery
what is lasik surgery
DuringLASIK surgery, a special type of cutting laser is used to precisely change the cornea to improve vision → With each pulse of the laser beam, a tiny amount of corneal tissue is removed.
advantages and disadvantages to lasik
ad - achieve20/20 vision or better
dis - Complications that result in a loss of vision are very rare + dry eyes and temporary visual problems such as glare, are fairly common.
what is Cataract surgery
for clouding of the lens (Fig. 18.15), which reduces the transmission of the light through
the lens.
The cloudy lens is removed from the lens capsule and an artificial lens is inserted → makes a very small incision in the eye and inserts a device that delivers high-frequency sound that breaks up the cloudy lens. The small lens particles are suctioned out and then an artificial lens is inserted into the lens capsule.
advantages and disadvantages of cataract surgery
ad - About 90% of eyes achieve
dis - complications of corneal swelling and/or inflammation in the eyes.
what are the 3 major processes of kidneys
- Filtration
- Reabsorption
3.Secretion
what is Filtration
blood travels from the heart via the aorta to the renal artery and into the kidney → renal arteries turn into smaller vessels that brunch off
until millions of capillaries are formed. Each capillary enters a nephron = forms the glomerulus
→ the glomerulus filters the blood, and the tubule returns needed substances to the blood and removes wastes (nitrogenous waste)
what is Reabsorption
returns essential components that have been filtered out of the blood back into the bloodstream
eg amino aids or glucose
what is Secretion
involves the removal of toxic substances from the blood capillaries and tissues surrounding the tubules and their active movement into the tubules for removal
→ metabolic wastes
- urea
- uric acid
what hormones are involves in the kidneys function
aldosterone
antidiuretic hormone (ADH
purpose of aldosterone
stimulates the reabsorption of salt in the loop of Henle, to regulate salt and
water balance in the kidney.
purpose of ADH
stimulates the reabsorption of water in the kidney
purpose of ADH
stimulates the reabsorption of water in the kidney
what are 2 technologies for loss of kidney function
- Renal Dialysis
- Transplant
what is renal dialysis
- dialysis machine, which pumps their blood through a system of tubes (coiled to increase their surface area and therefore the rate of diffusion), which have artificial semi-permeable membranes. The tubes are submerged in dialysis fluid, which flows in the opposite direction to the blood in order to maintain a concentration gradient to maximise diffusion.
advantages and disadvantages of renal dialysis
ad - remove metabolic wastes that have built up in the
person’s blood.
dis - Done 2-3x a week for 3-4 hrs
- process is only limited to the amounts of fluid/wastes can be removed from the blood; other substances such as sodium phosphate and potassium ions do not diffuse quickly enough and therefore may accumulate in the blood = patients have to follow a strict diet to prevent substances accumulating
what is kidney transplant
The best treatment for many patients with long-term kidney failure
→ renal transplant is the organ transplant of a kidney into a patient with end-stage kidney disease or loss of kidney function
advantages and disadvantages of kidney transplant
Advantages
- risks are generally lower than staying on dialysis
- Most kidney transplant patients live longer
- Fewer restrictions on what you can eat and drink
- Work and travel is easier
Disadvantages
- major operation and comes with surgical risks, like bleeding or rejection of the kidney with the immune system recognises kidney as non-self
- strong medicines to lower your immune system
- long waiting list
