semester 1 Flashcards WACE
what is homeostasis
the maintenance of a constant internal environment while fluctuations occur in the external environment
what is the endocrine system
a group of ductless glands which secrete chemical messages known as hormones to the bloodstream
what is a hormone
a chemical that is secreted by endocrine glands and that affects the functioning of the cell or organ. it is carried in the bloodstream
what are the key features of hormones
- target specific
- carried in bloodstream
- secreted by endocrine glands
- they are chemical messengers
- only affect the cell if they have receptors for that hormone
- change in the functioning of the cell
- mostly amines, proteins and steroids
- saturation can occur, when no more of that hormone can be used to alter the cell as their are no more receptors
- paracrines local hormones which secreted by cells and used in the same organ to increase communication
how do protein and amine hormones work
protein and amine hormones work by attaching themselves to the receptors cells on the membrane of the target cells, this usually causes a secondary messenger to be secreted which diffuses through the cell and activates particular enzymes(water soluble)
how do steroid hormones work
steroid hormones work by entering target cells and combining with receptor proteins inside the cell. the receptor may be on the mitocondria or other organelles in the nucleus. the hormone receptor complex can cause gene expression to begin
what is an endocrine gland
ductless, secretes hormones into extracellular fluid, usually passed through bloodstream
what is an exocrine gland
secretes into a duct that carries the secretion to the surface of the body
what hormones does the thyroid gland produce
thyroxine and calcitonin
what does both the thyroxine and calcitonin target
most cells
what is the action of the thyroxine hormone
stimulates metabolism, brings about the release of energy, monitors body temperature
what is the action of the calcitonin hormone
lowers blood calcium levels
what is the hormone produced from the paratyroid glamd
parathyroid gland
what does the parathyroid hormone target
bones, kidneys
what is the action of the parathyroid
to increase blood calcium levels
what hormone is secreted from the thymus
thymusin
what does the thymusin target
t-lymphocytes
what is the action of the thymusin
to influence the maturation and development of the t-lymphocytes
what hormones are secreted from the adrenal medulla
adrenaline(epinephrine)
noradrenaline(norepinephrine)
what does the adrenal cortex target
most tissues
what is the action of the adrenaline
targets many cells to prepare body for flight or respo\
what hormones are secreted form the adrenal crotex
- mineral carticoids
- glucorticoids
- gonadocorticoids
what does mineral corticoids target
kidney
what does glucorticoids target
most cells
what does gonadocorticoids target
testes
what is the action of the mineral carticoids
targets kidneys to reduce sodium concetration in urine and an icrease in potassium in unrine
what is the action of the glucocorticoids
stress responses, helps maintain normal glucose metabolism
what is the action of the gonadocarticoids
secondary sexual characterisitics
what hormones does the islets of langerhans secrete
beta cells(insulin) alpha cells(glucagon)
what does insulin target
most cells
what does glucagon target
liver and fat storage tissues
what is the action of the insulin
lowers blood glucose levels by promoting the uptake of glucose from blood to the cells of the body. acheived by the liver and skeleton muscles convert glucose to glucagon. fat storage tissues converts glucose to fats
what is the action of the glucagon
raises sugar levels in the opposite way to insulin. increases levels by promoting the breakdown of glycogon to glucose in the liver and the breakdown of fats
what hormones are secreted from the ovaries
oestrogen and progesterone
what does the oestrogen hormone target
many tissues
what does the progesterone target
uterus and mammary glands
what is the action of the progesterone and oestrogen
female secondary sexual characterisitics
development of the endometrium and the maintenance of the endometrium
hormone produced in the testes is
testosterone
what does testosterone target
many tissues
what is the action of the testosterone
male secondary sexual characteristsics
what hormones are secreted from the pituitary(anterior)
thyroid stimulating hormone adrenocorticotropic gonadotropic( FSH and LH) growth hormone prolactin
what does the thyroid stimulating hormone target
thyroid gland
what does the adrenocorticotropic hormone target
adrenal cortex
what does the follicle-stimulating hormone target
ovaries and testes
what does the lutenising hormone target
ovaries and testes
what does the growth hormone target
all cells
what does the prolactin target
mammary glands
what is the action of the thyroid stimulating hormone
regulates thyroid gland
what is the action of the adrenocorticotropic hormone
regulates adrenal cortex
what is the action of the follicle - stimulating hormone
ovaries - growth of follicles in ovaries
testes - production of sperm in testes
what is the action of the luteinising hormone
ovaries - ovulation and the maintenance of the corpus luteum
testes - secretion of testosterone from testes
what is the action of the growth hormone
growth of all cells and protein synthesis
what is the action of the prolactin
regulates milk production from mammary glands
what hormones are secreted from the pituitary(posterior)
antidiuretic hormone
oxytocin
what is the target for antidiuretic hormones
kidneys
what is the target for oxytocin
mammary glands
uterus
what is the action of the antiduretic hormone
regulates water absorption from kidneys
what is the action of oxytocin
allows milk letdown from mammary glands
stimulates contractions of uterus in labour
what is the hypothalamus
located at the base of the brain
regulates many of the basic functions fo the body
such as body temperature, water balance, heart rate
carried out through pituituary gland
what is the pineal gland
located deep inside the brain
size of the pea in children, gradually decreases
role remains a mystery
known to secrete the hormone melatonin which is involved in the regulation of sleep patterns
what does the stomach and small intestines secrete
they secrete hormones which coordinate the exocrine glands of the digestive system
what does the kidneys secrete
secretes hormones which stimulate the production of red blood cells in bone marrow
what does the heart secrete
secretes hormones which reduces blood pressure
what does the placenta secrete
secretes hormones during pregnancy need by the mother
what is the nervous system
the communication network and control centre of the body
what are the 2 parts of the nervous system
central and peripheral nervous system
what is the central nervous system
consists of the brain and spinal cord. this is the control centre of the nervous system
what is the peripheral nervous system
all other nerves that connect with the CNS and with the receptors, muscles and glands of the body
what specialised cells make up the nervous system
neurons
what is a neuron
basic structural and functional unit of the whole nervous system
what is the cell body of a neuron
contains the nucleus and other organelles of a cell
what is the dendrites
short extensions of the cell body that carry the nerve impulses into the cell body
what is the axon
usually a single long extension of the cell body that carries the nerve impulses away from the body
what can axons be covered in
axons can be covered in a layer of fatty material called myelin.
what forms the myelin sheath
schwann cells
what are the different functional neurons
sensory neurons
motor neurons
interneurons
what are the sensory neurons
carry messages from receptors in sense organs or skin to CNS
what are motor neurons
carry messages from the CNS to muscles and glands
what are interneurons
link sensory and motor neurons located within CNS
what are the different structures of a neuron
multipolar
bipolar
unipolar
what are multipolar neurons
have one axon and multiple dendrites, most common type
occurs in the brain, spinal cord and motor neurons that take messages to skeletal muscles
what are bipolar neurons
have one axon and one dendrite. both axon and dendrite may have branches at their ends. occur in eye, ear and nose where they take impulses from receptor cells to to other neurons
what are unipolar neurons
have just one extension - an axon
the cell body is off the the side of the axon
most sensory neurons that carry messages to the spinal cord are this type
what is a nerve fibre
any long extension of cytpolasm of a nerve cell, usually an axon
what is a nerve
a bundle of nerve fibres that are held together by connective tissue
what is a nerve impulse
the electrochemical change that travels along the membrane of a nerve cell; message is carried by a nerve
what is a synapse
the junction between 2 neurons or a neuron and a muscle or gland
what is a neurotransmitter
the chemical released into tiny gaps(synaptic cleft) which separates the 2 nerve cells
what is the neuromuscular junction
junction between a motor neuron and a muscle fibre. also called a motor end plate
what is action potential
when sodium ions move into a nerve cell at a particular place on the membrane; this change is transmitted along the cell membrane as a nerve impulse
what is polarisation
when a nerve is not firing an impulse, it is at rest
what is the membrane potential
the difference between the concentrations of ions inside and outside of the cell creates a potential between the inside and outside of the membrane
what is the resting membrane potential
membrane potential of unstimulated nerve cells - usually measured at about -70mv
what is the sodium potassium pump
actively moves ions across the membrane by transporting sodium ions out of the cell and potassium ions in the cell
what is the refractory period
when the nerve fibre cannot be stimulated to respond again. resting membrane potential must be restored first . (after an action potential, brief period)
what does the central nervous system consist of
brain, spinal cord and other nerves
what does the peripheral nervous system consist of
12 pairs of cranial nerves
- sensory fibres carry impulses towards CNS
- motor fibres carry impulses away from CNS
31 pairs of spinal nerves (from spinal cord)
joined to spinal cord by 2 roots, the ventral and dorsal roots
what is the ventral root
contains axons of motor neurons (cell bodies located in grey matter of spinal cord)
what is the dorsal root
contains axons of sensory neurons ( cell bodies located in the dorsal root ganglion - a small swelling in the dorsal root)
what is the ganglion
cluster of cell bodies /
what is the afferent divison in peripheral nervous system
carries impulses to CNS, made up of somatic and viseral
what does somatic neurons in the afferent division do
sensory neurons from skin and muscle
what does the visceral neurons in the afferent divison do
sensory neurons from internal organs
what is the efferent divison in peripheral nervous system
carries impulses from CNS
what does somatic neurons in the efferent division do
messages to skeletal muscles
what does the autonomic neurons in the efferent divison do
autonomic messages to heart and involuntary muscles/ glands
what does the autonomic sub-divison divide into
sympathetic and parasympathetic
descrition of autonomic
responsible for control of the internal environment of the body and usually checks outside of conscious control
description of somatic
responsible for carrying messages to skeletal muscles for which are under conscious control
effectors of autonomic
heart, muscle, involuntary muscles and glands
effectors of somatic
skeletals (suddenly muscles)
general function of autonomic
adjustment of the internal environment
general function of somatic
response to the external environment
efferent pathways autonomic
two more fibres crom the CNS to the effector with a synapse in the gangliom
efferent pathways somatic
one nerve fibre from the CNS to the effector. no synapse and no ganglion
neurotransmitters at effector for autonomic
acetylcholine or noradrenaline
neurotransmitter at effector for somatic
acetylcholine
set of nerves to target organ for autonomic
two sets - sympathetic and parasympathetic
set of nerves to target organ for somatic
one set
effect on target organ for autonomic
excitation or inhibition
effect on target organ for somatic
always excitation
control of autonomic divisions
involuntary
effect on target organ for somatic
always excitation
control for somatic cellsc
usually voluntary
control for somatic cells
usually voluntary
what is the general description for sympathetic divisions
generally produces responses that prepare the body for strenuous physical activity or situations that may involve aggression or fleeing from threat
what are the type of responses for sympathetic divisions
fight or flight
neurotransmitters for sympathetic division
nerve endings release noradrenaline
general description for para-sympathetic divisions
generally produces responses that maintain the body during restful conditions
neurotransmitters for para-sympathetic division
nerve endings release acetylcholine
what are the types of responses for para-sympathetic divisions
rest and digest
what happens in the central nervous system
incoming messages are processed and outgoing messages are initiated
what structures protect the delicate central nervous system
bone - cranium and vertebral canal
meninges membrane(3 layers)
cerebrospinal fluid
what is the cranium
part of skull that houses the brain
what is the vertebral canal
spinal cord runs through this opening
what are the meninges membrane
three layers of connective tissue form a membrane which covers the surface of the brain and spinal cord
what is the cerebrospinal fluid
fills between the middle of the inner layers of the meninges and circulates in the brain and a canal in the centre of the spinal cord
acts as a shock absorber and brings nutrients to the brain cells/ removes waste formed from blood and returns to blood.
what are the three layers of meninges
dura mater
arachnoid mater
pia mater
what is dura mater
though fibrous outer layer, sticks closely to the bones of the skull and the inside of the vertebral canal - but not as closely
what is arachnoid mater
mesh of loose fibres, more delicate to the dura mater. contains blood vessels and sticks closely to the brain and spinal cord
what is pia mater
thin layer which is firmly attached to the surface of the brain. impermeable to water(due to being covered in fat cells). blood vessels also piece through to the brain and spinal cord
what is the cerebrum
largest part of brain consists of the cerebral cortex basal ganglia convolutions(gyri) sulci fissures
what is the cerebral cortex
outer 2-4mm of brain made of grey matter
what is the basal ganglia
grey matter deep inside the brain
what are convolutions
folding patterns on the surface of the brain. increases surface area
what are sulci
shallow dips between convolutions
what are fissures
deep dips between the convolutions
what is the deepest fissure
the longitudinal fissure which separates the left and right hemispheres of the brain
what are the four main lobes of the brain
frontal
parietal
occipital
temporal
what is a tract
the white matter in the cerebellum contains bundles of myelinated nerve fibres which are usually called nerves outside the brain
what are the three types of tracts
tracts that connect various areas of the cortex within the same hemisphere
tracts that carry impulses between left and right hemispheres
tracts that connect the cortex to other parts of the brain or the spinal cord
what are the main functions of the cerebrum
thinking, reasoning, learning, memory, intelligence, sense of responsibility, perception of the five senses, initiation and control of voluntary muscle movements and more
what are the functional areas of the cerebral cortex
sensory areas - interpret messages from sensory neurons
motor areas - which control muscular movements
association areas - concerned with emotional and intellectual processes
what is the structure of the corpus callosum
large band of nerve fibres under cerebrum(at base of longitudinal fissure)
what is the function of the corpus callosum
nerve fibres across between the two hemispheres to allow the two sides of the brain to communicate
what is the structure of the cerebellum
folded into parallel ridges made of grey matter and there is white matter on the inner most section(branches out like a tree)
what is the function of the cerebellum
controls posture, balance, fine coordination of voluntray movement. all functions of the cerebellum take place below the conscious level
what is the location of the cerebellum
underneath and to the rear of the cerebrum
location of the hypothalmus
lies in the middle of the brain and cannot be seen from the outside
function of the hypothalmus
mostly concerned with maintaining homeostasis. regulates the ANS, body temperature, food and water intake, patterns of sleeping and waking, contractions of the urinary bladder, emotional responses and secretion of hormones
what is the medulla oblongata
a continuation of the spinal cord. about 3cm long. many nerve fibres pass through the medulla oblongata to get to the other parts of the brain
what is the function of the medulla oblongata
regulates reflexes such as sneezing, coughing and vomiting. regulates automatic body functions such as
cardiac centre - regulates heart beat and heart rate
respiratory centre - control rate and depth of breeding
vasomator centre - regulates diameter of blood vessels
nature of endocrine message
hormones
transport of messages for endocrine system
by the bloodstream
cells affected by endocrine system
all body cells
type of response from endocrine system
may be very general and widespread
time taken to respond for endocrine system
slower - from seconds to days
duration of response for endocrine system
long lasting - response may continue long after the stimulus has stopped
nature of message for nervous system
electrical impulses and neurotransmitters
transport of message for nervous system
along the membrane of neurons
cells affected by the nervous system
muscle and gland cells, other neurons
type of responses for nervous system
usually local and specific
time taken to respond in nervous system
rapid - within milliseconds
duration of response for nervous system
brief- stops quickly when the stimulus stops
what is a receptor
a structure that is able to detect change in the body’s internal or external environment
what are the types of receptors
thermoreceptors, osmoreceptors, chemoreceptors, touch/pressure receptors, pain receptors and photo/light receptors
where is the location of the thermoreceptors
hypothalamus(internal temp changes) and skin(external temp changes)
what do thermoreceptors detect
they detect hot or cold temperature
where is the location of osmoreceptors
hypothalmus
what do osmoreceptors detect
detect changes to osmotic pressure - to maintain water content
determined by the concentration of substances dissolved in water in the blood plasma
what is the location of chemoreceptors
located in nose(smell) mouth(taste) in many internal structures to monitor composition of body fluids and in some bv’s to monitor ph of the blood and co2/02 concentrations
what do chemoreceptors detect
detect chemical change
where are the touch/pressure receptors located
mainly in skin
what do touch/ pressure receptors detect
closer they are to the surface the more they detect light touch, deeper receptors are more sensitive to pressure and vibrations
what is the location of pain receptors(nocireceptors)
high number in skin and mucous membranes occur in most internal organs but not in the brain(the brain can’t hurt)
what do pain receptors(nocireceptors) detect
stimulated by damaged skin
where are photo/light receptors located
found in retina of eye rods for dim light and cones for colour vision
what do photo/light receptors detect
detect light and enable us to have vision
what is a reflex
a rapid, automatic response to change in the external environment
what are the reflex traits
starts from a stimulus in the external environment are involuntary - no conscious control by brain are rapid(small amount of neurons involved) are stereotyped - occur the same way each time
what is a reflex arc
the pathway a nerve impulse takes from receptor to effector
what is the flow diagram for a reflex arc
stimulus -> receptor -> CNS(spinal cord) -> effector -> response
what are the basic components of a reflex arc
- receptor - specialised cell or nerve ending of a sensory neuron
- sensory neuron - carry impulse to CNS
- synapse - at least one at this point (may not be from motor neuron to muscle)
- interneuron - interoperates information
- motor neuron - carry impulse to effector
- effector - carry out the response
some examples of reflexes
blinking when dusk particles/ objects come close to the eye
removing hand/ foot from hot/sharp objects
knee jerk
yawing
coughing
ducking
what us a learned reflex
not present from birth or not “innate” but learned overtime. more complex pathways
examples of learned reflexes
maintaining balance when riding a bike. breaking when driving a car to respond to something running into you
what is the tolerance limit in homeostasis
all cells have an optimal level to function - if not they will demature(upper and lower range of optimal level
what is a feedback system
a circular situation in which the body detects a change(stimulus) and responds to it, altering the original stimulus
what does a feedback system always involve
stimulus
receptor
modulator(control centre which processes the information)
effector
response(brings about the reaction)
feedback(the response to the original stimulus)
what is negative feedback
when the response is opposite to the stimulus
what is a positive feedback
when the response is to enhance the stimulus. eg contractions in labour and milk - letdown reflex
why is homeostasis important
cells of the body have particular conditions at which thet function at the optimum level/most effieciently. if these conditions are not met or fall too far above or below the optimum range, the cells could die
what is steady state
another way of describing homeostasis or maintaining the internal environment around an optimum level for cell functioning
what is tolerance limits
limits of factors(e.g core temperature, blood glucose limit) beyond which the modern will malfunction)
what is set point
the level at which a variable is to be maintained in a feedback system(e.g thermoregulation-core temperature)
what is dynamic equilibrium
the fluctuations above and below a set point as the body tries to maintain homeostasis
what is the difference between positive and negative feedback
negative feedback is in a homeostatic mechanism when the response is opposable to the stimulus. positive feedback is in a non-homeostatic mechanism which reinforces or intensifies the stimulus
what are the sick components of a feedback model
stimulus - change in environment receptor - detects change modular - control centre effector - carries out response response - change carried out feedback - what is achieved
what is the optimum level for human core temperature
36.8 degrees
how does dynamic equilibrium work in thermoregulation
to maintain the balance between heat loss and heat gain
what could happen if excess heat was not removed from the body
nerves could malfunction, proteins can change their structure and death could result
heat input for thermoregulation
from surrondings: conduction and radiation
from body processes - metabolism
heat out from thermoregulation
to surrondings(conduction/convection/ radiation)
evaporation of water from skin and lungs
warm air breathed out
warm urine/faeces expelled
how does metabolism/metabolic rate effect core temperature
during cellular respiration 60% of the energy produced is lost as heat energy which helps maintain core body temperature
the rate at which energy is released (metabolic rate) depends on many factors such as stress, exercise or even fever. during these times metabolic rate increases by up to 40 times, therefore heat production increases.
stimulation of the sympathetic nervous system causes noraderenaline to be released, which increases metabolic rate
what are the receptors and the modulator to core body temperature
peripheral thermoreceptors - in skin and mucous membranes(two types; hot and cold)
central thermoreceptors in hypothalamus
the hypothalamus receives the information in the temperature regulating centre and initiates the response
what is the role of the skin in thermoregulation
surface blood vessels and constrict/dilate to reduce increases heat loss via radiation, conduction and convection. this is controlled by autonomic nerves
sweat from sweat glands to increase heat loss via evaporation, controlled by sympathetic nerves.
water loss via lungs and mucous membranes contributes to heat loss
stimulus for high body temperature
increase in core temperature
receptors for high body temperature
peripheral thermoreceptors in skin and central thermoreceptors in hypothalamus
modulator for high body temperature
temperature regulating centre in hypothalamus
effectors for high body temperature
surface blood vessel
sweat glands
thyroid gland
cerebral cortex
response for high body temperature
vasodilation of surface blood vessels brings blood close the the surface/ away from core and increases heat loss via radiation
releases of sweat increases heat loss via evaporation
decrease in thyroxine levels to reduce metabolic rate, therefore reduce heat production
behavioural responses such as removing items of clothing
feedback for high body temperature
decrease core body temperature
stimulus for low body temperature
decrease in core body temperature
receptors for low body temperature
peripheral thermoreceptors in skin and central thermoreceptors
modulator for low body temperature
hypothalamus - temperature regulating centre
effectors for low body temperature
surface blood vessels skeletal muscles thyroid gland adrenal medulla cerebral cortex
response for low body temperature
vasoconstriction of surface blood vessels brings blood closer to the core and reduces heat loss via radiation
shivering - oscillating muscle tremors increases heat production
increase in thyroxine levels to increase metabolic rate, therefore increase heat production
secretes adrenaline and noradrenaline via sympathetic nerves. increases metabolic rates therefore heat production
behavioural responses such as putting on items of clothing, cross arms to reduce surface area for heat loss via radiation
feedback for low body temperature
increase core temperature
what are the tolerance limits
36.8 degrees is the optimum level
42 degrees is dangerous, 45 degrees can cause death. falling below 33-32 degrees can also cause death
what is heat stroke
when temperature and humidity is high it is difficult to lose heat via evaporation or radiation and thermoregulatory mechanisms may fall. leads to a person falling ill can be serious/fatal
what is heat exhaustion
caused by extreme sweating and vasodilation to lose heat. blood pressure and output decreases due to lack of water decreasing blood plasma volume. can cause fainting
what is hypothermia
caused by extreme cold. if core temperature drops below 33 degrees, metabolic rate slows so far that heat production cannot replace heat loss. can cause death.
what percentage of water are we
60%
what various fluids is water found in the body
2/3 intracellular fluid/cytosol(in cells)
1/3 extracellular fluid(outside cells and in blood plasma)(fluid between cells)
how do we intake water
food(70ml)
drink(1600ml)
metabolic rate(200ml)
how do we output water
urine - kidney(1500ml)
skin(500ml)
lungs(300ml)
faeces - alimentary canal (1200ml)
what is excretion
the removal of metabolic waste products
what is excreted from the lungs
excrete h20 and water. water is lost as water vapour during exhalation
what is excreted from the sweat glands
secrete water containing metabolic waste products such as salts
what is excreted from the alimentary canal
most materials in faeces are not considered metabolism wastes except bile pigments. water is lost with faeces
what is excreted from the kidneys
principle excretory organ as they are responsible for maintaining constant concentrations of materials in body fluids as well as removing wastes
what is the main role of the kidney
water regulation which therefore causes it to maintain composition of body fluids
what is the functional unit of the kidney called
nephron
where are the nephrons located
within the kidney
what is the pathway of urine which is produced
ureter-bladder-urethra
what are the three phases of urine production
filtration - most contents of blood(as high blood pressur) filters capsule, cells, protein stay in blood
reabsortion - useful materials reabsorb in blood
secretion - unwanted materials are passed into the filtrate
what is the composition of urine
95% water and solutes such as sodium, calcium and urea
what is osmotic pressure
measures the tendency of a solution to take in water via osmosis. it depends on the concentration of solute
how does antiduretic hormone play a part in osmotic pressure
controls the level of reabsortion at the distal convoluted tubules and collecting ducts. high ADH levels results in the tubules increasing their permeability to water, low level has the opposite effect
how does aldosterone play a part in osmotic pressure
controls level of sodium being reaborbed to blood and potassium being secreted to urine. high aldosterone increase both of these. water is reabsorbed along with sodium, therefore also works to regulate water levels in blood/blood volume. increasing blood volume also increases blood pressure. therefore aldosterone also regulates blood pressure
stimulus for increase osmotic pressure/ decrease plasma volume
increase osmotic pressure/ decrease plasma volume
receptor for increase osmotic pressure/ decrease plasma volume
osmoreceptors in thirst centre of hypothalamus
modulator for increase osmotic pressure/ decrease plasma volume
thirst centre in hypothalamus
effector for increase osmotic pressure/ decrease plasma volume
posterior pitituary
nephrons
adrenal cortex
response for increase osmotic pressure/ decrease plasma volume
release ADH
ADH causes distal convoluted tubule and collecting ducts to become more permeable to water, therefore more water is reaborbed, increasing blood volume.
release aldosterone
also acts on nephrons to increase reabsortion of sodium ions to blood. water is also reabosrbed with the sodium, therefore increase water in plasma
feedback for increase osmotic pressure/ decrease plasma volume
decrease osmotic pressure/ increase plasma volume
stimulus for decrease osmotic pressure/ increase plasma volume
decrease osmotic pressure/ increase plasma volume
receptor for decrease osmotic pressure/ increase plasma volume
osmoreceptors in thirst centre of hypothalamus
modulator for decrease osmotic pressure/ increase plasma volume
thirst centre of hypothalamus
effector for decrease osmotic pressure/ increase plasma volume
posterior pitituary
nephrons
adrenal cortex
response for decrease osmotic pressure/ increase plasma volume
inhibits release of antiduretic hormone
reduction in ADH causes the distal convoluted tubule and collecting duct to become less permeable to water. therefore less water us reabsorbed, decreasing blood volume.
inhibits release of aldosterone
also acts on the nephrons to decrease reabsortion of sodium ions to blood. water is also reabsorbed with the sodium, therefore decrease water in plasma
what is dehydration
water loss exceeds water gain
may be caused by excessive sweating, vomiting, diarrhoea, lack of thirst reflex on old people, lack of water
causes severe thirst, low blood pressure, dizziness and extreme headache: extreme cases: death
what is water intoxication
when fluids become excessively diluted and cells take in too much water via osmosis.
balance of electrolytes is out, therefore not enough salts/water in body. can be caused when a person with severe dehydration attempts to drink water, but does not intake salts, can cause death
what is the form of sugar in blood
glucose
why is glucose needed in continual supply
source of energy for cells(cellular respiration)
how do we gain glucose
food
what carries blood from the intestines and stomach to the liver
the hepatic portal
what is the role of liver in blood glucose level
glucose may be used for liver function
converted to glycogen for storage
continue to circulate in blood
converted to fat for long term
what is the role of the pancrease in blood glucose level
islets of langerhans contain alpha and beta cells
alpha cells secrete glucagon to stimulate glycogenolysis (glycogen to glucose)
beta cells secrete insulin to stimulate glycogenesis(glucose to glycogen)
role of adrenal glands
adrenal cortex(stimulated by ACTH) secretes cortisol and adrenal medulla, secretes adrenaline/noradrenaline increases metabolic fat, promotes gluconeogenesis
what is glucose
form of sugar in blood
what is glucagon
hormone secreted by the alpha cells which raises BGL
what is glycogen
stored form of glucose
what is glycogenesis
glucose to glycogen insulin stimulates
what is glycogenolysis
glycogen to glucose glucogen stimulates
what is glyconeogeneis
producing glucose from fats, proteins and amino acids. when glucose levels are too low
stimulus for increase blood glucose level
increase BGL
receptor for increase blood glucose level
beta cells(islets of langerhans)
modulator for increase blood glucose level
beta cells
effector for for increase blood glucose level
beta cells
liver
adrenal cortex
adrenal medulla
reponse for for increase blood glucose level
release insulin, promotes uptake of glucose by cells and protein synthesis
liver converts glucose to glycogen for storage in liver (glycogenesis) and fat storage.
inhibits cortisol secretion which reduces glycogeonolyis =- reducing blood glucose
inhibits secretion of adrenaline/noradrenaline. inhibits glycogenolysis in liver - reducing blood glucose levels
stimulus for decrease blood glucose level
decrease BGL
receptor for for decrease blood glucose level
alpha cells (islets of lanerghans pancreas)
modulator for decrease blood glucose level
alpha cells
effectors for decrease blood glucose level
alpha cells, liver, adrenal cortex, adrenal medulla
response for decrease blood glucose level
release glucagon, promotes glycogen to be convterted to glucose (glycogenolyisis)
liver glycogenolyis, gluconeogenesis
secretes cortisolwhich stimulates conversion of amino acids into glucose
secretes adrenaline and noradrenaline which stimulates glycogenolyisis - increasing blood glucose
what happens when glucose levels exceed tolerance limits
hyperglycaemia - abnormally high BGL
hypoglycaemia - abnormally low BGL
what is type 1 diabetes
insulin dependant, child onset, immune system atatcks beta cells and tehrefore cannot pruduce insulin
what is type 2 diabetes
non-insulin dependant
adult onset - lifestyle disease, produce insulin but cells do not response to this
what do all cells need a constant supply of
oxygen, carbon dioxide,
what must be removed continuously from the body
oxygen, carbon dioxide
how can the amount of carbon dioxide and oxygen change in blood
changes in breathing
how is circulatory system involved in regulation of gas concentrations
involved to circulate blood to the lungs
how does the control of breathing work
diaphragm and inercostal muscles contract/relax
due to stimulation by nerve impulses from phrenic nerve
respiratory centre location in medulla oblongata(centre of inhalation and exhalation)
chemoreceptors detect changes in gases
what is monitored in regulation of gas concentration
under normal circumtances oxygen levels play little part in breathing regulation
carbon dioxide levels
hydrogen ion concentrations
why is hydrogen ions monitored in regulation of gas concentration
co2 + h20 - h2c03 - h+ + hco3-
when co2 dissolves in water it form carbonic acid which breaks down into h+ and hco3-
smallest amounts of change effects breathing rate
where are the receptors located in regulation of gas concentration
o2 - chemoreceptors in aortic and carotid bodies, medulla oblongata
co2 - central and peripheral chemoreceptors, medulla oblongata
h+ - chemorecepors in aortic and carotid bodies
stimulus for increase in co2/h+ or decrease Ph (breathing rate regulation)
for increase in co2/h+ or decrease Ph
receptor for for increase in co2/h+ or decrease Ph (breathing rate regulation)
central and peripheral chemoreceptors(medulla oblongata/aortic and carotid bodies)
modulator for increase in co2/h+ or decrease Ph (breathing rate regulation)
respiratory centre in medulla oblongata
effector for increase in co2/h+ or decrease Ph (breathing rate regulation)
diaphram and intercostal muscles
response for increase in co2/h+ or decrease Ph (breathing rate regulation)
increase rate of contraction and therefore increase breathing rate ], which in turn increases rate of gas exchange (o2 in, co2 out)
feedback for increase in co2/h+ or decrease Ph (breathing rate regulation)
for decrease in co2/h+ or increase Ph
why do we experience heavy breathing during exercise
muscles require larger amounts of oxygen and produce large amounts of carbon dioxide. therefore increases the demand of oxygen exchange
what is hyperventilation
rapid, deep breathing, voluntary or from stress
provides more oxygen and removes more carbon dioxide then required
usually corrects self, over prolonged time, it can cause person to pass out
how and why can breathing be controlled voluntarily
speech, protective(not breathing around irritating particles or underwater) bypasses medulla oblongata and is controlled by cerebral cortex
cannot hold breathe forever: co2 builds up and respiratory centre is triggered
why is the output of blood from the heart important
maintains homeostasis of gases in bodily fluids
what is heart rate
number of heart beats per minute
average resting heart rate for an adult is 70bpm. varies greatly depending on many factors such as age,gender, fitness…
what is stroke volume
volume of blood forced out with each contraction
what is cardiac output
amount of blood leaving the heart every minute
cardiac output is SV x HR
what is blood pressure
force at which blood presses on the walls of the blood vessels, depends on cardiac output and diameter of blood vessels
what is blood pressure affected by
cardiac output - increase co2, increase BP - therefore affected by gas concentration
diameter of blood vessels: dilated reduces Bp, constriction increase Bp
controlled by autonomic nervous system(sympathetic or parasympathetic stimulation)
volume of plasma in blood: high volume of water over salts reduces Bp, higher volume of salts over water increase Bp(aldosterone) - therefore fluid affected by fluid regulation
what are the regulations of heart rate
nodes, autonomic nervous system, chemoreceptors, cardiac centre
how does nodes regulate heart rate
controlled by the sino-atrial node and atrioventricular node which control the contraction of the heart muscle
SA node stimulates nerve impulse which spreads over the atria, causing contraction
the impulses reaches the AV node and stimulates it to send a nerve impulse over the ventricles, causing contraction
how does autonomic nervous system regulate heart rate
under the influence of the ANS can be acted on by either sympathetic or parasympathetic division
requires a balance between the two
how does chemoreceptors regulate heart rate
chemoreceptors in aortic and carotid bodies detect changes
how does the cardiac centre regulate heart rate
cardiovascular regulating centre: (or cardiac centre) is located in the medulla oblongata
any increase in CO2 concentration or decrease in Ph will influence the cardiac centre to increase cardiac output as well as trigger the response previously discussed
what is the stimulus for increase in co2/h+ or decrease Ph (heart rate regulation)
increase in co2/h+ or decrease Ph
what is the receptorsfor increase in co2/h+ or decrease Ph (heart rate regulation)
central and peripheral chemoreceptors(medulla oblongata/aortic and carotid bodies)
modulator for increase in co2/h+ or decrease Ph (heart rate regulation)
respiratory and cardiovascular centres in the medulla oblongata
effectors for increase in co2/h+ or decrease Ph (heart rate regulation)
diaphragm and intercostal muscles
adrenal medulla
heart muscle
response for increase in co2/h+ or decrease Ph (heart rate regulation)
increase rate of contraction and therefore increase breathing rate, which in turn increases rate of gas exchange (o2 in co2 out)
secretes adrenaline/noradrenaline which increases the stimulation on the SA node
increase stimulation by SA node cause heart rate muscle to increase rate and strength of contractions, therefore increase heart rate
feedback for increase in co2/h+ or decrease Ph (heart rate regulation)
decrease in co2/h+ or increase Ph
what happens to a person with diabetes
a diabetic person either does not produce enough insulin or their cells are not resistant to it. this throws out the balance between insulin and glucagon which regulate BGL causes hyperglycaemia (abnormally high levels of blood glucose)
how does someone recieve type 1 diabetes and what are the effects and treatments
usually begins in childhood
fault in the persons immune system causes destruction of beta cells, therefore insulin is not produced
in most cases this can be managed by insulin injections or an insulin pump under the skin
long term effects can cause kidney failure, stroke, amputations nerve damage and blindess
how does someone recieve type 2 diabetes and what are the effects and treatments
develops in adults (usually 45 years and over)
able to produce insulin but cells do not respond to it as they have become resistant
therefore body cells do not uptake glucose or limited from blood
lifestyle disease - preventable
treatment includes managing diet and exercise
what happens to a person with a form of thyroidism
under secretion of thyroid hormones thyroxine and tri-iodothyronine(both have the same effect to regulate metabolism)
how does someone recieve hyperthyroidism, what are the effects and what treatment is there
too much thyroxine
most common form is graves disease - enlargement of thyroid caused by an immune system reaction
cells are over stimulated so can cause rapid heart bear, weight loss, increase appetite, sweating, anxiety, protruding eyeballs
treatment: include drugs to block thyroids use of iodine or can be given a radioactive iodine drink which kills thyroid cells
how does someone recieve hypothyroidism, what are the effects and what treatment is there
not enough tyroxine
can be due to problems with thyroid, pituitary or hypothalamus
lack of iodine - means thyroid gland cannot produce its hormones
causes enlarged thyroid - goitre
hypothyroidism can also be caused by an immune system attack - hashimoto’s disease or even surgery to remove the thyroid such as if a person has thyroid cancer
more symptoms: slow heart rate, weight gain, lack of energy
treatment: more iodine in diet, hormone replacement tablets
how does someone receive human growth deficiency
essential for normal growth and metabolism
synthesised and secreted by the anterior pituitary gland
deficiency can cause growth retardation or dwarfism
can result from disease or can be inherited
affected children can be injected with HGH
what drugs have similar effects to neurotransmitters
caffeine, alcohol, amphetamine/methamphetamine, MDMA/ecstasy, cocain, heroin
what effect does caffeine have
mimics adrenaline
what effect does alcohol have
depresses CNS, stimulates insulin production and inhibits antiduretic hormone
what effect does amphetamine/methamphetamine have
release adrenalin, dopamine and seratonin - neutrotransmitters
what effect does MDMA/ecstasy have
initiates flight or fight
what effect does cocaine have
blocks removal of noradrenaline, dopamine and serotonin therefore stimulates CNS
what effect does heroine have
binds to receptors to decrease pain, slows breathing rate, decreases blood pressures and body temperature
what effect can poor eating habits have
inadequate nutrition can lead to vitamin and mineral deficiency diseases
lack of the following: iodine, iron(anaemia, reduced oxygen carrying capacity of blood, haemoglobin) vitamin B12(pernicious anaemia) vitamin k(essential for blood clotting)
balancing energy intake and output is essential for homeostasis. appetite and body weight are crucial factors in maintaining this balance. high fat diets throw out balance
what effect can excessive exercise have
compulsive/excessive exercise can mean that proteins in muscles are needed to be broken down for energy and muscle mass is reduced
places great stress on the heart and calcium in bones can be decomposed
amenorrhea - in females who exercise excessively menstruation stops - conserves energy
what is emphysema
lung disease which breaks down the alveoli walls
results in less surface area for gas exchange therefore not enough oxygen can be taken in
most common cause is smoking
incurable
over time oxygen tubes/masks may need to be used
what is fever
can result from infectious diseases - therefore not a disease itself but a symptom of a disease
increase in body temperature
can help fight off infection but can distrupt homoestasis
what is hypertension
occurs when homeostatic responses cannit keep blood pressure within normal limits
significantly increase risk of cardiovascular problems and kidney failure
risk factors include obesity, lack of exercise, excessive slat intake and excessive alcohol intake
what are injuries
many injuries can directly effect homeostasis
e.g excessive blood loss limits supply of oxygen and glucose to cells and the removal of wastes, punctured lungs impairs gas exchange, immobility limits squeezing action on veins therefore decreases venous returns, spinal cord injuries can damage nerve impulses require to reach effectors such as diaphragm or other muscles
what is a communicable disease
also known as infectious or transmissible disease
disease caused by foreign organisms invading the body and multiplying there. these disease causing micro-organisms are known as pathogens
some communicable diseases are contagious - meaning they can be passed on by direct contact with a person who has the disease, or by direct contact with an object touched by another person.
what is a pathogen
disease causing micro-organism
what are the four types of pathogens
fungi, bacteria, virus, parasites
what is a virus
requires an electron microscope to be seen
contain genetic material (DNA or RNA) covered in protein coating
DNA or RNA causes multiplication of virus within the affected living cell
new virus particles can leave infected host and infect others
bacteriophages are viruses that attack bacteria
not all viruses are harmful
examples of viruses
HIV/AIDS, bird flu, chickenpox, herpes, glandular fever, hepatitis, rubella
what is bacteria
single cell organisms
microscopic
classified based on shape
majority of bacteria are not harmful to humans(non-pathogenic)
bacteria decomposes organic material and can be used in industrial processes(cheese and yoghurt)
in humans bacteria lives in large amounts on skin and in the intestines(aiding in digestion)
examples of bacteria
chlamydia, cholera, gastroenteritis, gonorrhoea, leprosy, peptic ulcers, pneumonia
what is fungi
do not commonly affect humans
mostly diseased that effect skin
can be useful fungi such as mushrooms and yeast
examples of fungi
ringworm, thrush, tinea
what is a parasite
organisms that live on or in another living thing(the host) ang gain shelter and food from it
can cause little to lots of harm
ectoparasites live on the surface of the body
endoparasites live inside the body
examples of parasites
ectoparasites - fleas and lice
endoparasites - roundworms and protozoans
what are the 6 transmissions of pathogens
physical contact, droplets, bodily fluids, ingestion, airborne, vectors
how is physical contact a pathogen transmission
either directly(touching an infected person) or indirectly(touching an object that has been touched by an infected person)
examples of physical contact diseases
skin infections and STI’s
how is bodily fluids pathogen transmission
blood or other bodily fluids come in contact with mucous membranes or the bloodstream.
examples of bodily fluids diseases
HIV, hepatitis B and C
how is droplets a pathogen transmission
droplets of moisture containing the pathogen be emitted when breathing, talking, etc
these droplets can settle on food or food utensils
examples of droplet diseases
cold, flu, measles
how is indigestion a pathogen transmission
contaminated food/drink
examples of indigestion diseases
salmonella
how is airborne a pathogen transmission
evaporated exhaled droplets that are inhaled
examples of airborne diseases
various viruses
how is a vector a pathogen transmission
via other mammals such as insects either directly by bite or indirectly by contaminated food etc
examples of vector diseases
maleria(mosquito), lyme disease(ticks)
what are the two catergories for the bodies defences
non-specific defences and specific defences
what are the bodies non-specific defences
work against all pathogens
body’s first line of defence
what are the bodies specific defences
directed at a particular pathogen
e.g if you get chickenpox your body creates antibodies for chickenpox so you become immune and cannot contract them again. these antibodies wont work for any other viruses though
what are the seven external defences
skin, mucous membranes, hairs and cilia, acids, lysosome, cerumen and urine
what role does skin have as an external defence
provides a barrier. provided it is not broken, its relatively impermeable to micro-organisms
oil glands secrete sebum which contains substances that kill pathogenic bacteria - sweat can also prevent micro-organism growth
what role does mucous membranes have as an external defence
body cavities open to the exterior contain nucleus that aims to stop the entry of micro-organisims. the whole digestive, urinary and reproductive tract is protected this way
what role does hairs and cilia have as an external defence
nasal cavity contains hairs and mucous which helps nose trap about 90% of particles and micro-organisms that are breathed in
cilia are tiny hair like projections from cells which beat to move trapped micro-organisms towards throat where they can be coughed up or swallowed.
what role does acids have as an external defence
acidic juices in stomach, acidic secretions of the vagina and slight acidity of sweat helps kill micro-organisms
what role does lysozyme have as an external defence
found in tears, sweat, nasal secretions and saliva. cleanses and kills bacteria
what role does cerumen have as an external defence
aka ear wax, protects from infections. also contain some lysozyme
what role does urine have as an external defence
flushing action cleanses the urethra and prevents bacterial growth
what is a reflex action
autonomic, involuntrary response to a stimulus. the four reflexes that protect against diseases are sneezing, coughing, vomiting and diarrhoea
what are phagocytes
cells that can engulf and digest micro-organisms and cell debris
how is sneezing a protective reflex
irritation on walls of nasal cavity
fumes, dust particles(likely to be carrying pathogens)
forceful expulsion of air carries the irritant out
how is coughing a protective reflex
irritation of lower respiratory tract(bronchi and bronchioles)
forceful expulsion of air carries out irritant - forces mucous and foreign particles up towards throat and mouth
how is vomiting a protective reflex
in reference to protection against disease, vomiting is stimulated by bacterial toxins in the stomach
contractions of the diaphragm and abdominal muscles causes vomiting
stomach contents are expelled
how is diarrhoea a protective reflex
irritation of intestines(bacteria, viruses or some animal parasites)
causes increased contractions of muscles in intestine walls so irritant moves quickly along. not enough time for water reabsortion so faeces is very watery
what is a leucocyte(white blood cell)
different types
all have a role in phagocytosis
leucocytes leave the blood capillaries and move through body tissues to the site of infections or injuries
some secrete substances that destroy bacteria before they are engulfed and others engulf the live bacteria and then digest them
what are macrophages
large phagocytic cells that develop form some leucocytes
can be ‘wondering cells’ that move through tissues searching for pathogens to destroy, while others are fixed in one location and only destroy pathogens that come by them
macrophages either release a substance to destroy the micro-organisms or engulf and digest them
what is inflammation
a response to damaged tissues
what is the purpose of the inflammatory response
reduce the spread of pathogens, destroy them and prevent the entry of any more pathogens
reduce damaged tissue and cell debris
begin the repair of damaged tissue
what are the 4 signs of inflammation
redness, heat, pain, swelling
what are the seven steps in the inflammatory response
mast cells histamine heparin phagocytes pain receptors pus mitosis
what is the role of the mast cells in the inflammatory response
special cells present in almost all tissues, stimulate and co-ordinate inflammation by releasing chemicals including histamine and heparin
what is the role of histamine in the inflammatory response
increases blood flow to the area and causes the walls of the blood capillaries to become more permeable so extra fluid can be filtered from the blood which causes the swelling. the increased blood flow causes redness and heat
what is the role of heparin in the inflammatory cycle
prevents blood clotting in the immidiate area of the injury. however, a clot of fluid around the damaged area does form inhibiting the spread of pathogens to healthy tissues
what is the role of phagocytes in the inflammatory cycle
attracted to the area by chemicals released by mast cells. the leucocytes and macrophages then consume macrophages and debris
what is the role of pain receptors in the inflammatory cycle
the abnormal conditions of the damaged tissues stimulates pain receptors in this area, therefore the person feels pain
what is the role of pus in the inflammatory response
the phagocytes (filled with bacteria, debris and dead cells begin to die themselves. the dead phagocytes and tissue fluid form a yellow liquid called pus
what is the role of mitosis in the inflammatory response
new cells are produced by mitosis to repair the damaged tissues
what is a fever
elevation of body temperature (above 37 degrees) as a result of infection
what does a fever aim to do
inhibit bacterial/viral growth and speed up the rate of chemical reactions for cell repair
what happens to body temperature during fever
still regulated but always at a higher level
how does the body try to conserve heat during a fever
via vasoconstriction, causing the person to feel cold and also shivering can occur to increase heat production
what happens when the fever breaks crisis point
vasodilation will occur and the person may feel hot and sweat a lot
what is the most likely reason for the body thermostat to be reset
a substance called pyrogens secreted by white blood cells during the inflammatory response
when can a fever result in death
when it is 44.5-45.5 degrees
what is the lymphatic system
a network of lymph capillaries joined to large lymph vessels, some of which contain lymph nodes along them
what is the purpose of the lymphatic system
to collect fluid that escapes from the “leaky” blood capillaries and return it back to the circulatory system, has a role to play in defending the body
what is good hygiene
to reduce the risk of infections with pathogens:
-wash hands:especially when preparing food, before eating, after using the toilet, before administering first aid, after coughing/sneezing
-cover mouth when coughing/sneezing
- wear gloves/ safety glasses when cleaning blood/bodily fluids
-disinfect surfaces
never share personal items such as tooth brushes, razors
what are mechanical barriers
provide obstacles for pathogens therefore reduce the risk of infection/disease
examples:
surgical masks
gloves
safety glasses
protective clothing
barrier contraceptive devices (e.g condom)
what is the immune response
also known as the homeostatic response, protects against foreign organisms/ chemicals/ cancerous or abnormal cells. it is comprised of different types of cells found in most organs of the body
what are the non-specific cells
include phagocytes(engulf organisms and cell debris)
what are specific cells
include b cells and t cells which provide protection against specific micro-organisms/disease-causing substances
when these cells react - it is called the immune response
what are the two parts of the immune response
antibody-mediated immunity and cell-mediated response
what role does lymphoid tissue have
both aspects of the immune response require lymphoid tissue
found mostly in the lymph nodes but also in the spleen, thymus and tonsils
composed of two types of lymphocytes involved in the immune response(b cells and t cells)
b-cells and t cells are both produced in bone marrow and find their way to the lymphoid tissue - however each take different routes
what route does t-cells take to get to the lymphoid tissue
half of the cells produced go to the thymus to mature before moving to the lymphoid tissue
what route does b-cells take to get to the lymphoid tissue
half of the cells mature in the bone marrow before moving to the lymphoid tissue
what are antigens
any substance capable of causing a specific immune response (body will produce antibodies)
antibody - mediated and cell mediated immunity are triggered by antigens
information on antigens
large molecules and can be proteins, carbohydrates, lipds and nucleic acid.
could be a whole organism or part
any toxin produced by a bacteria is also called an antigen
an antigen could even be a foreign blood type blood cells or pollen
what are self antigens
large molecules produced in the persons own body that do not cause immune response
what are non-self antigens
foreign compounds that do cause the immune response
what is an antibody
specialised protein produced in response to a non-self- antigen
what is the antigen-antibody complex
antibody produced in response to an antigen combined with an antigen
what is the active site
where the antibody and antigen combine. fit together like a lock and key
what is the antibody-mediated immunity
aka humoral response
involves production and release of antibodies in blood and lymph
provides resistance to viruses, bacteria, and bacterial toxins before these micro-organism can enter the body’s cells
involves b cells found in lymphoid tissue
different b cells are capable of responding to different antigens
how does the antibody - mediate process happen
antigen activates b cells
b cells enlarge and divide into a group of cells called a clone
most clones become plasma cells which secrete the specific antibody needed
antibody will then circulate the blood, lymph and extracellular fluid until it attaches to the active site of the specific antigen
other b cells(that do not become plasma cells become memory cells)
memory cells spread to all body tissues of if a subsequent invasion occurs the response will be very quick
what is a primary response
first exposure to the antigen that comes on immune response
can be fairly slow- days needed to build up enough antibodies
b cells need time to multiply and differentiate into plasma cells
leaves the body with a memory of the particular antigen
what is a secondary response
subsequent exposures to the same antigen
immune response is much quicker due to memory cells
plasma cells can form more rapidly and antibody levels will rise
it can be so quick that symptoms would likely be not felt by the individual
what do the antibodies actually do
combine with foreign enzymes or bacterial toxins or inactivate them so they cannot react with any other cell pr compound
bind to the surface of viruses and prevent them from entering a cell
coat bacteria so they can be more easily consumed by phagocytes
cause agglutination of foreign cells
dissolve organsism
turn soluble substances into insoluble substances so phagocytes can consume them more easily
what is cell mediated immunity
aka cellular immunity
provides resistance to many things including : the intercellular phase of bacterial and viral infections, resistance to fungi and parasites, it is involved in rejection of transplant tissue and also important in fighting cancer cells
involves t cells(t lymphocytes)
occur in lymphoid tissue
different types of responses to different specific antigens
t cells will only become activated or sensitised in response to a particular antigen. after b cells or a macrophage encounter the antigen and brings it to a lymph node where the t cells are
what is the process of cell mediated immunity
the sensitised t cells enlarge and divide, giving rise to a clone(group of identical t cells)
some cells remain in the lymphoid tissue as memory cells
memory cells will recognise the antigen if it ever presents again and initiate the immune response much faster
the other t cells that do not become memory cells continue to develop further into a possible three other types of t cells
what are killer t cells
cytotoxic
migrate to site of infection to deal with antigen
attach to antigen and secrete a substance that will destroy it
it then goes off in search for more antigens to destroy
what are helper t cells
do play a role in antibody-mediated response as well they secrete various substances that : - cause lymphocytes at the infection site to become activated and intensify the response attract macrophages (to destroy by phagocytosis) intensify the activity of phagocytes and macrophages
what are suppresor t cells
these cells release a substance to inhibit b cells and t cells
this is needed when the injection has been dealt with as if the immune response was too excessive
what is immunity
resistance to infections by micro-organism
what is natural immunity
occurs without human interaction
what is artificial immunity
occurs from giving people an antibody or antigen
what is passive immunity
person is given antibodies
what is active immunity
person is exposed to an antigen and the bodt makes its own antibodies
what is natural passive immunity
antibodies enter the bloodstream across the placenta or in breast milk
what is artificial passive immunity
antibodies are injected into the bloodstream
what is active natural
ability to manufacture antibodies results from an attack of a disease
what is artificial active
ability to manufacture antibodies results from being given an antigen by vaccination
what are antibiotics
drugs that are used to fight infections or micro-organisms, particularly bacteria
what are bactericidal antibiotics
kill bacteria by changing the structure of the cell wall or cell membrane. or by disrupting the actions of enzymes
what are bacteriostatic antibiotics
stop bacteria from reproducing. usually by distrupting protein synthesis
what are broad spectrum antibiotics
antibiotics effective on a wide range of bacteria
what are narrow spectrum antibiotics
antibiotics effective only on specific bacteria
what are super bugs
bacteria that have a resistance to an antibiotic
what is multi bug resistant
when a type of bacteria is developing or has developed resistance to more than one antibiotic
what is total drug resistance
no antibiotic is still effective against the infection
what are antiviral drugs and why is it difficult to find drugs suitable for antivirals
drugs used for treating viral infections
they inhibit the development of the virus
it is available for HIV, herpes, hepatitis A and C, and influenza
it is difficult as viruses use the hosts cells to duplicate, therefore substances that can be used to disrupt the virus would also likely disrupt the hosts cells too
