Coordination Flashcards
How does response occur
Stimulus (change in surrounding ), receptor organ detects change in environment , contraction of muscles of the effector organ brings the response
How does saliva respond to smell of food
Nose is the receptor then glands secrete saliva
What is the link between stimulus and response
Nervous system where information in nerve cells is transmitted by nerve impulses.
What is the role of the receptor
Detect the stimulus by changing its energy into the electrical energy of nerve impulses e.g. Eat converts sound energy into nerve impulses . This is called transduction , all receptors are transducers of energy
What is the name for a nerve cell
A neurone
What is the CNS
Brain and spinal cord , impulses from receptors pass along nerves containing sensory neutrons until they teach the brain and spinal cord
What do motor neurones do
Transmitt impulses to muscles and glands
What are dendrons
Part of the CNS for motor neurones , outside CnS for sensory . Cytoplasmic extensions which in turn from finer extensions called dendrites
What are synapses
Junctions
Axon
Longest extension of the neurone , carries impulses to the effector organs . At the end of the axon it divides into many nerve endings which connect with a muscle at a synapse called the nerve muscle junction . Signals from nerve impulses transmitted across the nerve muscle junction causing the muscle to contacts .
Sheath
Covers the axon and made of myelin which insulates the axon preventing short circuits with other axons and speeds up conduction of impulses
Sclera and cornea and iris and pupil
Outer coat of the eye , at the front becomes the cornea which let lights into the eye . Behind cornea is the iris which has a hole called the Pupil that lets light through but is black to stop light escaping from the inside of the eye
Choroid
Underneath sclera . Contains pigment which stops light being reflected around inside the eye .
Retina
Intermost layer of the bAck of the eye where light energy is transduced into electrical energy of nerve impulses . Retina contains rods and cones that react to light producing impulses in sensory neurones that pass impulses to the brain through the optic nerve , can’t distinguish between different colours in dim light as cones can’t work . Cones are concentrated at centre of retina called gives and give a sharper image than rod
Lens
Light is refracted and inverted then the brain interprets the image the right way round
How does the iris work
Changes the amount of light entering the eye by changing the size of the pupil . Contains circular muscles that form a ring shape in the iris and radial muscles.
What happens in bright light
Stimulus light intensity , retina is the receptor , sensory neurones in the optic nerve go to an unconious part of the brain , motor neurones in the nerve to the iris cause in bright light circular muscles contact and radial muscles relax so pupil constricts , dim light circular muscles relax radial muscles contract and the pupil dilates . This is a reflex action as too bright light would damage rods and cones and too dim light would not form an image
What is the blind spot
No image as this is where optic nerves leaves the eye so no rods and cones
What is accomadation
Changes in the eye which allow us to see objects at different distances. Lens shape changes . If focusing on a distant object ciliary muscles relax suspensory ligaments pulled tight and the lens is flat for less refraction as rays of light are almost parallel when they reach cornea
If focusing on close object ciliary muscles contract suspensory ligaments slacken and the lens is more rounded for more refraction because light rays spread out when entering the ye so they need to be focussed on the retina through refraction
What is a reflex
Specific very fast automatic unconscious response to a stimulus to protect from harm
Relay neurone
Make up brain and spinal cord have no long axon but can form synopses with other neurones
What is the reflex arc
Stimulus detected by receptors which generate impulses in density beyond that enter CNS through aadorsal root ( part of the spinal cord ) , connect by synapses with short relay neurones that connect with motor neurones which emerge through the centra toot and send impulses out to the muscles.
Stimulus , receptor , sensory neurone ,CNS relay neurone CNS, motor neurone , effector response
Grey matter
Middle of spinal cord nerve cell bodies , white matter is outer part of spinal cord as there are many axons with fatty myelin sheaths .
How do synapses work
Impulses arrive down axon dendrites secrete neurotransmitter which diffused through the synaptic cleft and attaches to the membrane of the second neurone that starts off impulses in the second cell and is then broken do n by enzymes
Relay neurone
Found only in CNS
Nerve
Bundle of neurones
Negative feedback
System where changes are reversed and factors are returned back to a certain level
Cerebrum
Source of concious thoughts has sensory areas and motor areas
Cerebellum
Coordinates muscles behind the cerebrum . Underneath is the medulla and connects spinal chord with the brain
Pituary gland
Base of brain and secretes hormones part of the hypothalamus
Exocrine glands
Products secrets through ducts whereas endocrines secrete hormone into blood .
When do hormones work
If cells of tissue or organ have special chemical receptors for the hormone e.g. Liver has insulin receptors
Differences between nervous and endocrine system
Nervous is faster but has shorter effects and very localised whereas endocrine takes slower as hormones travel slower and take longer to act but the response is longer lasting and they can have widespread effect
ADH
Pituary gland controls water content of the blood . Collecting ducts become more permeable so more water is reabsorbed into blood
Insulin
Secreted from the pancreas and lowers blood glucose whrrras glucagon raises blood glucose . It stimulates liver to take up glucose and convert it into glycogen lowering blood sugar as if blood sugar is too high plasma will have low water potential and cause cells to loose water and shrink . Glucagon makes cells of liver and muscles break glycogen into glucose .
What is diabetes
CAnt make enough insulin and someone with diabetes will have glucose in their urine . They will also be thirst because high blood glucose stimulates receptors in THE hypothalamus so the person drinks to dilute their blood . Mild diabetes can be controlled by limiting carbs , more serious diabetes needs insulin injections
What is excretion
Removal of metabolic waste
What is urea
Excess nitrogen waste as it can’t be stored
Kidney function
Controls water and salt concentration in the body and is an excretory organ
Osmoregulation and exertion
How does blood leave and enter the kidney
Enters through renal artery , blood is filtered to remove water salt and urea and passes outbm through the renal vein . The urine passes out the kidneys through ureters and is stored in the bladder . Sphincters outside urethra relax and urine is released
How does kidney work
Blood enters into Arterioles into the nephron and is filtered into the glomerulus where proteins are filtered out through the basement membrane as they are too large. The glomerular filtrate enters the bowmans capsule . As it passes along the primary coil all glucose is absorbed back into blood in the second coiled tubule water is reabsorbed . Urine passes out. Through the collecting duct
How and why do the kidneys make more concentrated Urine
This is how kidneys regulate water content if the blood . If blood is too concentrated anti directic hormone is released and the collecting duct is made not permeable to water , so a small volume of concentrated Urine is released because the kidney tubules are more permeable to water whereas a diuretic blocks release or ADH making the collecting duct very permeable to water causing a large volume of dilute urine because kidney tubules are las permeable
What is an edotherm
Looses heat from the inside
What happens if your body is too hot
Skin is a sense organ and sends impulses to the hypothalamus in the thermoregulatory centre . Sweat glands then produce large amount of sweat because when sweat evaporates energy is supplied by the bodies heat cooling the body down . Hair erector muscles pull hairs up trapping air so heat is lost to air . Vasodilation occurs and blood vessels dilate and blood flow is increased to the Skins surface meaning more heat is radiated
What happens if your body is too cold
Hairs are pulled up by hair erector muscles to trap air to insulate the body . Vasoconstriction occurs and capillaries constrict so blood flows through deeper muscles not near surface of the skin meaning less heat is lost .this is brought about by sphincter muscles
What is a tropism and what are the different kinds
Tropism - growth in response to a stimulus e.g. Phototropism , positive moment to light of shoots
Negative movement of roots Geotropism positive movement of roots negative moment of shoots
Hydrotropism positive moment of roots .
Positive is towards stimulus , negative is away from stimulus
How are plant tropismos brought about
Eg on a shoot auxin accumulates on lower side of shoot causing shoot to bend upwards as auxin changes the rate of elongation in plant cells . If auxin is diffused evenly Plant will grow straight up ,
