11 animal physiology Flashcards
when do muscles exert force
when they contract and not when they relax and lengthen
how many directions can muscles cause movement in
only one
what does there need to be for opposite movements
a pair of muscles that exert muscles in opposite directions - an antagonistic pair of muscles
what is the anchorage
one end of the muscle which is the firm point of attachment that does not move when the muscle contracts
what shape are typical muscles
elongated
examples of anchorages and insertions in humans
bones
examples of anchorages and insertions in arthropods
the exoskeleton
what is the opposite end of the muscle from the anchorage
insertion
how do bones and exoskeletons act as levers
they can change the size and direction of the force exerted by a muscle.
what are the junctions between bones called
joints
give the two general overall types of joints
fixed joints
joints that allow movement (articulation0
what are the three main parts of synovial joints
cartilage covering the surface of the bones to reduce friction where they could rub against each other
synovial fluid between the cartilage covered surfaces to lubricate the joint and further reduce friction.
joint capsule that seals the joint and holds in the synovial fluid
what are ligaments
tough cords of tissue connecting the bones on opposite sides of a joint.
ligaments attach
bone to bone
tendons attach
muscle to bone
function of ligaments
they restrict movement and help to prevent dislocation. they also ensure that certain movements can occur at a synovial joint but not at others. e.g. the elbow allows a lot of movement in one plane of bending or straightening, but little in the other planes
biceps…
the flexor muscle, used to bend the arm at the elbow
humerus bone…
provides a firm anchorage for the muscles
triceps…
the extensor muscles, used to straighten the arm
joint capsule…
seals the joint
synovial fluid…
lubricates the joint to reduce friction
cartilidge
a layer of smooth and tough tissue that covers the ends of the bones where they meet to reduce friction
ulna…
bone that is the insertion for the triceps and acts as a lever transmitting forces from the triceps through the forearm
radius…
bone that is the insertion for the biceps and acts as a lever transmitting forces from the biceps through the forearm
tendon…
attaches muscle to bone
distal
furtherst away e.g. for the thigh bone, it is the end by th knee.
proximal
closest e.g. for the thigh bone, it is the end by the torso.
dorsal
upper
ventral
underside
explain how the tendons work in the leg of an insect
the tendons at the distal end are attached to the opposite sides of the exoskeleton of the tibia, so one of them is a flexor of the joint between the femur and tibia and the other is an extensor.
what are synovial joints
joints that allow movement or articulation. they mostly consist of the same three parts.
synovial joints usually consist of
cartilige
synovial fluid
joint capsule
upper part of an insect leg
femur
lower part of an insect leg
tibia
ankles of a insect leg
spur (the pointy thing towards its head and tarsus, the whole ankle.
what term refers to the number of nuclei skeletal muscle fibres have
multinucleate
what do skeletal muscle fibres contain
specialised endoplasmic reticulum
why are muscles that are used to move the body called skeletal muscles
because they are attatched to bones
types of muscle
straited (stripes)
smooth
cardiac
what is sarcolemma
a single plasma membrane surrounding a muscle fibre
why are muscle fibres longer than usual cells
embryonic muscle cells fuse together to form muscle fibres
what is the sarcoplasmic reticulum
a modified version of the endoplasmic reticulum.
function of the sarcoplasmic reticululm
it wraps around every myofibril, conveying the signal to contract to all parts of the muscle fibre at once. it stores calcium.
what are inbetween the myofibrils
large numbers of mitochondria, providing the ATP needed for contractions
what are myofibirils
the many parallel, elongated structures within each muscle fibre. they have alternating light an dark bands, the stripes of the straited muscle, going across each myofibril
what is in the centre of the light myofibrils
a disc shaped structure, referred to as the z line
what is each myofibril made up of
contractile sarcomeres
what is the part of the myofibril between one z line and the next called
sarcomere, the functional unit of the myofibril
what are the two types of protein filament
thin actin filaments
thick myosin filaments
where are actin filaments attatched
to a z line at one end
where are mysosin filaments attatched
theyre interdigiated with actin filaments at both ends and occupy the centre of the sarcomere.
how many actin filaments surround an actin filament
six, and they from cross bridges during muscle contraction
what area of the myofibri does the thick myosin filaments relate to
the dark areas
what is the z line on the myofibril
the light band, whilst the thin actin filaments continue and the thick myosin filaments stop.
within each muscle fibre are cylindrical structures called
myofibrils
around myofibrils there is
a specialised type of endoplasmic reticulum. there are also mitochondria between the myofibrils
what do myofibrils consist of
repeating units called sarcomeres
describe the bands in sarcomeres
light and dark
what do skeletal muscle consist of
large multinucleate cells called muscle fibres
a sarcomere contains thin
actin filaments
a sarcomere contains thick
myosin filaments
what is at either end of a sarcomere
a z line
describe the heads of myosin
they have heads that form cross bridges by binding to the actin
what part of the sarcomere is dark
the part containing myosin
what part of the sarcomere is light
the part containing actin
what goes down the middle of the sarcomere
the m line
what band is the middle of the sarcomere
A band
what band is inbetween the z line and m line
I band
what zone is the middle of the sarocmere
H zone
what is skeletal muscle contraction
the sliding of actin and myosin filaments sliding over eachother. this pulls the end of the muscles together, making the muscle shorter
what is required for sliding filaments and muscle contraction
ATP.
describe the hydolosis of ATP
3 adenanine moelcules and 3 phosphate groups. one phosphate group is broken down into energy for aerobic respiration to become ADP
types of muscle
cardiac
smooth
skeletal
what causes muscles to contract
action potential
how do muscles know to contract ?delete?
an electrical signal of action potental opens calcium channels.
ca2+ ions flood in the fibre, triggering neurotransmitters to move onto the next cell across the synapse
the neurotransmitters attatch to the sodium pathway which allow sodium ions to pass through.
these sodium ions depolarise the sarcoplasmic reticulum which can then release stored ca2+ ions into the cell cytoplasm which cause muscle cells to contract
the mechanism of muscle contraction
myosin filaments have heads which form cross bridges when they are attatched to binding sites on actin filaments.
ATP binds to the myosin heads and causes them to break the cross bridges by detatching from the binding sites.
ATP is hydrolysed to ADP and phosphate, causing the myosin heads to change their angle. the heads are now ‘cocked’ in position, as they store potential energy from ATP.
the heads attatch onto binding sites on actin that are further from the centre of the sarcomere than the previous sites.
the ADP is released and the heads push the actin filaments inwards towards the centre of the sarcomere. this is called the powerstroke.
how do muscles know to contract
an electrical action potential causes an influx of Ca2+ ions.
the influx of Ca2+ triggers the synaptic vesicles full of neurotransmitters to move across the synaptic cleft (synapse)
the synaptic vesicles bind to sodium channels and they open. (as they couldn’t previously.)
now soidum can travel through the channels to the sarcoplasmic reticulum. (this is aided by a concentration gradient)
the positive Na+ ions means the membrane (which was positive on the outside and negative on the inside) has flipped, this is called depolarisation.
this means the sarcoplasmic reticulum releases loads of Ca2+. this becomes the stored ca2+ ions.
skeletal muscle fibres are …
multinucleate
what is the sliding filament theory of muscle contraction
when a muscle contracts, the actin is pulled along myosin toward the centre of the sarcomere.
the actin and myosin filaments become completely overlapping.
there is no pale area in the centre.
the muscle shortens.
what do catalytic converters do
remove CO, NOx, and unburned hydrocarbons from exhaust gases, making them CO2, N2 and H2O
what do catalytic convertes have to make them have a large surface area
a ceramic honeycomb coated with a thin layer of catalyst metals (Pt, Pd, Rh)
why is blood in the glomerulus under high pressure
because the diameter of the afferent ateriole is wider than the effering ateriole
what is the entering ateriole called
afferent
what is the leaving ateriole called
efferent
what is the filtration membrane made of
glycoproteins, surrounding the endothelium of the capillaries
what does the inner layer of the bowmans capsule consist of
highly adaptive podocytes
what prevents proteins an cells passing through the bowmans capsule
largegaps between podocytes
what passes through bowmans capsule
glucose, ions, water, urea etc
stages of the nephron
renal artery glomerulus bowmans capsule proximal convoluted tubule loop of henle distal convoluted tubule collecting duct
what does the liver do
cleans the blood
glucose present in the filtrate is…
actively transported out of the proximal convoluted tubule into the tissue fluid surrounding the nephron, using energy from mitochondria
how much of the sodium and chlorine ions are actively transported out of the proximal convoluted tubule, using a Na pump in the basal membrane
90%
what do cotransporter proteins do
bring in glucose and amino acids
contransporters bring in glucose and amino acids, establishing a conc gradient between…
the filtrate and the tissue fluid outside.
contransporters bring in glucose and amino acids, establishing a conc gradient between the filtrate and the tissue fluid outside. this causes…
water to move out of the filtrate down a water potential gradient by osmosis
what are the most permable (freely permable) to water parts of the nephron
the proximal convoluted tubule and descending limb of the loop of henle
which part of the nephron is impermeable to water
the ascending limb
which parts of the nephron have variable permability to water
the distal convoluted tubule
what do metabolic processes produce
waste
what type of waste is nitrogenous
protein waste
what are osmoregualtors
the organisms that are able to keep or regulate the solute concentration of their body fluids above or below that of their external environment.
they control the osmolarity of their tissues within very narrow limits.
when you become dehydrated…
urine darkens
skin becomes less elastic
heart rate and breathing rate increase
blood pressure decreases.
is the renal artery or renal vein nearer the top of the kidney
the renal artery, then renal vein
endothelial cells are
the inner layer of cells
epitherial cells are
the outer layer of cells
function of loop of henle
create a high concentration of sodium ions and chlroide ions in the tissue fluid of the medulla
why does the loop of henle perform its function
so that water can be reabsorbed from the contents of the nephron as they pass through collecting duct
survival advantage of the loop of henle
very concentrated urine can be produced
conserves water and prevents dehydration
the descending limb of the loop of henle is
water permable
the ascending limb of the loop of henle is
more permeable to salts/less permeable to water
which part of the loop of henle is the descending limb
the thick part
why is the glucose conc in the renal vein slightly lower than that of the renal artery
some of the glucose is reabsorbed for metabolic processes
why is the oxygen concentration lower in the renal vein than in the renal artery
some of the oxygen is used in the metabolic processes
why is the carbon dioxide concentration higher in the renal vein than in the renal artery
due to the production of carbon dioxide during respiration in the cells of the kidney
each kidney has around
1 000 000 nephrons
bowmans capsule function
Highly porous wall which collects the filtrate
glomerulus function
Knot-like capillary bed where high-pressure filtration takes place
proximal convoluted tubule function
Twisted section of the nephron where water, nutrients and salts are reabsorbed back into the blood; contains many mitochondria and microvilli
loop of henle function
Hairpin shaped tube with a descending and ascending limb; water and salt reabsorption takes place here
distal convoluted tubule function
Another twisted section of the nephron, where water and salts are reabsorbed back into the blood; also contains many mitochondria and microvilli
collecting duct
A slightly wider tube that carries the filtrate to the renal pelvis
afferent ateriole
Brings blood from the renal artery
efferent ateriolle
A narrow blood vessel that restricts blood flow, which helps to generate the pressure needed for filtration
vasa recta
An unbranched capillary shaped like the loop of Henle, with the descending limb bringing blood deep into the medulla
what are podocytes
the cells of the inner walls of the bowmans capsule. They have many extensions which fold around the blood capillary forming a network of filtration slits that hold back the blood cells during ultrafiltration with the help of the glomerular basement membrane.
what is the basement membrane made of
glycoproteins
what are the small window like openings called in capillaries
fenestrations
wwhere does ultrafiltration take place
fenestrations
the fenestrations in the capillary wall allow WHAT to flow out and WHAT to come in
The fenestrations in the capillary wall allow blood to flow out, however, the basement membrane acts like a sieve during the ultrafiltration process and stops the blood cells and large proteins. Thus, white and red blood cells cannot pass through, but small proteins, salts and nutrients can.
what do cells of the proximal convluted tubule have
lots of mitochondria to provide energy for active transport
does the tissue fluid deep in the medull have a high or low water potential/salt concentration
low water potential
high salt concentration
where is blood taken away from the kidneys
via the renal vein connecting to the inferior vena cava
what does the ureters connect
urine from the kidney to bladder
where does a nephron begin and end
in the cortex and the looop of henle moved down into the medulla
where is the basement membrane
inbetween the glomrulus and the bowmans capsule
what type of pressure is there inside the glomerulus capillaries
hydrostatic build up
what substances travel from blood plasma to glomerulur filtrate
water inorganic ions urea uric acid glucose amino acids
what substances travel from blood plasma to glomerular filtrate
water inorganic ions urea uric acid glucose amino acids
what si ficls law
rate of diffusion = surface area x conc gradient
/ length of diffusion pathway
what is ficks law
rate of diffusion = surface area x conc gradient
/ length of diffusion pathway
what substances are reabsorbed back into the blood during selective reabsorbtion
all glucose, amino acids, vitamins, and many Na and Cl ions are reabsorbed out of the PCT and back into the blood
what do outer membranes of cells actively transport (kidneys) out of cytoplasm and where does this substnace go
sodium ions (sodium potassium pump) down a conc gradient back into the cytoplasm, passing through co-transporter proteins that transport glucose or amino acids
what does selective reabsorbtion of salts, glucose and amino acids do
reduce the water potential of cells
increase water potential in tubules
keep water via osmosis
outline the function of the proximal convoluted tubule
selective reabsorbtion of water, glucose, minerals, useful substances
absorption by active transport
what is the medulla (hyper…)
tonic
what does the cortex do
ultrafiltration
explain the process of ultrafiltration
blood in the glomerulus is under high pressure caused by the difference in diameter of afferent and efferent arterioles.
fluid plasma and small molecules forced into bowmans capsule
which prevents larger molecules or blood cells from passing through
where is the loop of henle
in the medulla
where is the nephron (except LOH)
in the cortex
if molecules are left behind after ultrafiltration they they exit through
the efferent ateriole
podocyte function
helps support structure of glomerulus
what does fennestrated mean
has holes in it
what do the endothelial fenestrationd in the glomerulsus do
allow all small molecules to pass through (water, urea, ions etc, NOT large proteins)
what does the different sizing of aterioles in the glomerulus do
create blood pressure theat gives hydrostatic pressure that brings about filtration
what is the basement membrane
the filtration membrane
in the lumen of the PCT, what happens to Na+
it is actively transported back using atp energy from mitochondria.
in the lumen of the PCT, what happens to all glucose and AA
reabsorbed by co transporter proteins (Na diffuses in providing energy for the exchange.
in the lumen of the PCT, what happens to water
absorbed by osmosis
what is in the glomerular filtrate
H2O
salt urea
glucose
AA
what do the microvilli around the lumen of the PCT do
increase SA
what is the purpose of the LOH
to make the surrounding tissues (or medulla) more salty, this helps to concentrate urine and reabsorb water via osmosis (higher conc grad).
the descending limb is impermeable to…
and permeable to..
impermeable to Na+
permeable to H2O
the ascending limb is impermeable to…
and permeable to..
impermeable to H2O
permeable to Na+
why is the descending limb first
so that we dont get rid of too much water, and so it can concentrate the filtrate before the ascending limb
what is an aquaporin
small protein pores in the collecting duct that make it permeable to water. adh constructs these temporarily, as the collecting duct is usually impermeable to water.
chemical formula for ammonia
NH3
chemical formula for urea
(NH2)2CO
chemical formula for uric acid
C5H4N4O3
ammonia toxicity
high
urea toxicity
moderate
uric acid toxicity
low
animals that produce ammonia
aquatic animals (because ammonia is very soluble and can dissolve in the water)
animals that prouce urea
terrestrial animals (most land animals convert ammonia to urea or uric acid which require less water for excretion and they are less toxic than ammonia)
animals that produce uric acid
reptiles and birds
how to make more effective kindeys
maybe lengthen loop of henle
saltier medulla tissue
what is osmoregualtion
the process by which organisms regulate the water content of the body
what do osmoreceptors do
montior water potential of the blood and vary the amount of ADH released into the bloodstream. the kidneys respond to a change in ADH conc by adjusting the vol and conc of the urine
mammals are osmoregulators. what do they need to do
ensure the volume of blood plasma and concentration of dissolved substances in the blood and tissue fluid stay relatively constant.
what do osmoconformers do
keep the osmotic potential of their bodies the same as their sea water environment.
how do marine invertebrates keep the osmotic potential of their bodies the same as their sea water environment
they take in ions and salts but (sharks) also accumulate high levels of urea which increases the concentration of solutes in their body.
how do amoeba osmoregualte
they use contractile vacuole which contracts and expels water out of the cell.
how do insects osmoregualte
they have malphigian tubes that control water balance and excrete nitrogenous waste.
how do mammals osmoregualte
the kidney:
excretes urea
controls the balance of water and salt
how do fish osmoregualte in a freshwater environment
drinks little water, actively takes up ions through gills, absorbs water through skin and excretes dilute urine.
how do fish osmoregulate in a saltwater environment
drinks ample water excretes ions through gills, loses water through skin
give 4 examples of organisms that are osmoconformeres
sharks
jelly fish
sea cucumbers
sea fish
how do contractile vaculoes help osmoregualte
it uses active transport to pump ions into the CV. water then enters by inward osmosis and then is released into the surrounding environment by exocytosis.
how do malphigian tubes help osmoregualte
MT collect excess water from blood in the insect’s abdomen and pass it onto the hind gut of the digestie system. more water can be absorbed here.
how do kidneys help osmoregualte
kidney nephrons collect excess water from the blood through ultrafiltration. this water collects in the kidney pelvis and is stored in the bladder for urine.
where does ADH act
in the DCT and CD
where is ADH secreted from
pituitary glandf
what monitors solute concentration in the blood
osmoreceptors in the hypothalamus
what is an aquaporin
Aquaporins are membrane proteins. They initiate a series of events which causes vesicles with aquaporins to fuse with the surface membrane. The aquaporin then allows water molecules to pass through
what does the binding of ADH to the receptors in the cell membranes in the collecting tubules cause
increased water permabiliy by causing aquarporin to move to the surface membrane. the aquaporin then allows water molecules to pass through,
primary causes of kidney failure
diabetes and hypertension or high blood pressure
what is dialysis
Hemodialysis is a process that uses an artificial membrane known as dialysis tubing (found within the dialyser) to remove wastes, such as urea, from the blood as well as to restore the proper balance of electrolytes in the blood and eliminate extra fluid from the body.
how does dialysis work
The dialyser is made up of two parts, one for your blood and one for a washing fluid called dialysate. The dialysis tube is a thin membrane that separates these two parts. During hemodialysis, blood cells, protein and other important molecules remain in your blood because they are too big to pass through the membrane. Smaller waste products in the blood, such as urea, creatinine, potassium and extra fluid, pass through the membrane and are washed away in the dialysate.
alternative to dialysis
kidney transplant
what would too much glucose in the urine indicate
diabetes
what would too much protein in the urine indicate
ultrafiltration process failing
waht does erythrocytes in urine indicate
severe infection or tumour
what would blood or leuocyctes inurine indicate
infection or kidney tumour
why do insectes exrete uric acid
This molecule has very low solubility in water and is excreted as a semisolid form in insect faeces. This allows water conservation.
where does spermatogenesis take place
semi inferous tubules in testes.
in the geminal epithelium of the semi inferous tubules, there are
stem cells which form spermatogonia.
what does spermatogonia divide by mitosis to produce
additional spermatogonia (2n) and primary spermocytes (2n)
waht do primary spermocytes divide by meiosis I to produce
two lots of secondary spermocytes (n)
what do secondary spermocytes divide by meiosis II to produce
spermatids (n)
what do spermatids divide to produce
sperm with the nursing of sertolli cells
what is multiplication phase in spermatogenesis
spermatogonia –> primary spermocytes
what is growth phase in spermatogenesis
primary spermocytes –> secondary spermocytes
what is maturation phase in spermatogenesis
secondary spermocytes –> spermatids
what is spermiogensis in spermatogenesis
spermatids –> sperm
where does oogenesis occur
ovaries, in the primary follicle, where there is a primaru oocyte surrounded by a single layer of follicle cells
what does the oogonium from germinal epithelium diide by mitosis to produce
oogonium (2n)
what does the oogonium (2n) divide by mitosis to produce
primary oocyte (2n)
what does the primary oocyte divide by mitosis to produce
polar body (n) and secondary oocyte (n)
what does the secondary oocyte produce involving ovulation
2nd polar body fertilised egg (2n)
stages of fertilisation of a human egg
arrival of sperm binding acrosome reaction fusion cortical reaction mitosis
arrival of sperm in fertilisation
sperm attracted by a chemical signal and swim up the oviduct to reach the egg. fertilization is only successful if many sperm reach the egg.
binding in fertilization
the first sperm to break through the layers of the follice cells binds to the zona pellucida. this triggers the acrosome reaction.
acrosome reaction in fertlization
the contents of the acrosome are released by the separation of the acrosomal cap from the sperm. enzymes from the acrosome digest a route for the sperm through the zona pellucida, allowing the sperm to reach the plasma membrane of the egg.
fusion in fertlization
the plasma membranes of the sperm and egg fuse and the sperm nucleus enters the egg and joins the egg nucleus. fusion causes the cortical reaction.
cortical reaction in fertilzation
small vesicles called cortical granules move to the plasma membrane of the egg and fuse with it, releasing their contents by exocytosis. enzymes from the cortical granules cause cross linking of glycoproteins in the zona pellucida, making it hard and preventing polyspermy.
mitosis in stages of fertilzation
the nuclei from the sperm and egg do not fuse together. instead, both nuclei carry out mitosis, using the same centrioles and spindle of microtubules. a two cell embryo is produced.
what happens after the mitosis stage in fertilization
a hollow ball of cells called a blastocyst is formed and cells begin to differentiate.
the zygote has become an embryo and next implants into the uterus lining
if the embryo successfully implants it will keep growing and produce hCG hormone.
hCG hormone causes the ovary to continue producing progesterone - pausing the menstrual cycle
what basic stages are in both spermatogenesis and oogenesis
mitosis generates large numbers of male gametes in the testes
cells grow so that the cells have enough resources to undergo two divisions of meiosis.
meiosis to undergo haploid cells.
differentiation so the haploid cells develop into gametes with structures needed for fertilization.
which part of the seminiferous tubule divide endlessly by mitosis to produce more diploid cells
the outer layer called germinal epithelium cells
the diploid cells formed by the endless mitotic divisions of the germinal epithelium become
primary spermocytes.
what does each primary spermocyte form (via meiosis I)
two secondary spermocytes
what does each secondary spermocyte form (via meiosis II)
two spermatids
what do spermatids form
spermatozoa
what happens once spermatozoa become sperm
the sperm detatch from sertolli cells and are eventually carried out of the testis by the fluid in the centre of the semiinferous tubule
what does the acrosome contain
enzymes that digest the zona pellucida around the egg
where is the haploid nucleus
underneath the acrosome.
what is the haploid nucleus
contains the 23 chromosomes that are passed from father to offspring.
what does the tail of the sperm do
provide propulsion that allows the sperm to swim up the vagina, uterus and oviduct until it reaches the egg.
where is the centriole in the sperm
between th head and midpiece
what do the helical mitochondrion do in sperm
produce ATP by aerobic respiration to supply energy for swimming and other processes in the sperm.
what do the microtubules do in the sperm
make the sperm tail beat from side to side and generate the force that propel the sperm
what do the protein fibres do in the sperm
strengthen the tail
which cells in the womans ovaries divide by mitosis to form more diploid cells
the germinal epithelium cells
what do the diploid cells formed by the germinal epithelium cells in the ovaries do
grow into larger cells called primary oocytes
what do primary oocytes do
start the first division of meiosis but stop during prophrase I. the primary oocyte and a single layer of follicle cells around it form a primary follicle.
how many primary follicles are there in a newborn girl
400, 000
what does the primary oocyte complete and form
the first division of meiosis, forming two haploid nuclei. the cytoplasm of the primary oocyte is divided unequally, forming a large secondary oocyte and a small polar cell.
what does the secondary oocyte start
the second division of meiosis but stops in prophase II. the follicle cells meanwhile are proliferating and follicular fluid is forming.
what happens when the mature follicle burts at the time of ovulation
the egg that is released is still the secondary oocyte.
what happens after fertilisation in the ovaries
the secondary oocyte completes the second division of meiosis to form an ovum (with a haploid nucleus inside) and a second polar cell or body. the first and second polar bodies do not develop and eventually degenerate.
PAGE 140 PHOTO
STAGES IN SPERMATOGENESIS
PAGE 141 PHOTO
STAGES IN OOGENESIS
what is the cytoplams/yolk in a mature human egg used for
droplets of fat and other nutrients needed during early stages of embryo development.
what do the cortical granules do in the mature egg
harden the zona pellucida to prevent multiple fertlization
what does the zona pellucida do in the mature egg
protects the egg cell and restricts entry of sperm.
what are the layer of follicle cells in a mature egg called
corona radiata
significant differences between spermatogenesis and oogenesis
millions of sperm produced by men every day from puberty.
only one egg produced each 28 days for women.
nearly all the cytoplasm is removed during the latter stages of spermatogenesis so sperm contain very little.
egg cells contain more cytoplasm than any other human cell.
species that partake in internal fertilisation
humans + mammals
pythons + reptiles
albatrosses + birds
species that partake in external fertilisation
salmon + fish
frogs + amphibians
what is polyspermy
fusion of two or more sperm with an egg cell results in a cell that has three of each chromosome or more. this is called polyspermy. cells produced in this way often die and those that survive are often sterile.
where do sperm swim
vagina cervix uterus oviducts if there is an egg in the oviduct, the sperm can fuse with it to produce a zygote
describe zygote to blastocyst
divides by mitosis to form a 2 cell embryo, then a 4 cell embryo until it becomes a blastocyst
where is the blastocyst transported
down oviducts to uterus. at 7 days, the embryo implants itself into the endometrium. if implantation doesnt occur then the embryo is not supplied with enough food and dies.
how and where does the ovum divide after fertilisation
by mitosis in the oviduct
what happens whilst he embryo migrates down the oviduct to the uteurs
it divides even more
what is a blastocyst
an embryo with about 125 cells
what is the outside of the blastocyst
zona pellucida
what is the trophoblast
the outer layer of cells
what is the blastocoel
a fluid filled blastocyst cavity
what is the embryoblast
inner cell mass
where does the blastocyst implant
the endometrium (lining) of the uterus
BLASTOCYST
DIAGRAM
after the egg cell reserves are used up what happens
the zona pellucida breaks down allowing the balstocyst to implant into the uterine wall. Finger like projections grow into the uterine wall and will develop into the placenta, allowing the embryo to access external supplies of the required nutrients.
how does the endometrium not shed during pregnancy
continued production of progesterone and estrogen. early in pregnancy, the embryo’s outer cells that will develop into the placenta starts to produce hCG stimulating the corpuus luteum to continue the production of progesterone and estrogen. hCG remains until the placenta is fully established and can take over the role of progesterone an estrogen secretion.
what connect the embryo to the endometrium (?)
fingerlike projections, chorionic villi. they produce max imum surface area for contact with the maternal blood.
placenta diagram
!
where do the chorionic villi project to
the intervillous space, where maternal blood collects. he fetal blood circulates in capillaries which lie very close to the surface of the villus, with only a few micrometres separating them from the maternal blood pools. This short distance facilitates diffusion between the maternal blood and the fetal blood.
functions of the placenta
Exchange of material to keep the fetus alive during pregnancy (see Table 1 ).
Production of progesterone and estrogen. At the beginning of the pregnancy, this task is performed by the corpus luteum. However, the activity of the corpus luteum progressively decreases from the beginning of the eighth week. Its role is entirely replaced by the placenta at the end of the first trimester (about 12 weeks).
what passes from mother to fetus via diffusion
oxygen
drugs
alcohol
what passes from mother to fetus via facilitated diffusion
glucose
amino acids
vitamins
minerals
what passes from mother to fetus via osmosis
water (and back from fetus to mother)
what passes from mother to fetus via endocytosis
hormones (and back from fetus to mother via exocytosis)
what passes from mother to fetus via receptors
some viruses like HIV
what passes from fetus to mother via diffusion
carbon dioxide
waht passes from fetus to mother via facilitated diffusion
urea
what do the two fetal arteries (or umbilical arteries) bring from fetus to placenta
deoxygenated blood
what does the fetal or umbilical vein bring
oxygenated blood back from the placenta to fetus
describe the correlation between size or mass of animal and gestation period
positive
how is birth signalled to happen
the fetus signals to the placenta to stop producing progesterone, triggering the secretion of oxytocin, produced by the posterior lobe of the pituitary gland and by the fetus. the estrogen continues to rise, inducing the development of oxytocin receptors on the muscles of the uterine wall, increasing the responsiveness of the uterus to oxytocin
what starts uterine contraction
the endometrium secretes prostaglandins
what happens as more and more oxytocin is released
contractions become stronger and stronger
what is prolactin
the hormone ahat is produced by the anterior pituitary gland, stimulating milk production
causes of estrogen pollution
widespread use of contraceptives like estradiol
consequences of estrogen pollution
lowering sperm count in maels
when does the embryo implant into the endometrium
after about 7 days
as body mass increases,
so does gestation period
what secretes hCG
human embryos
what does hCG do
stimulates the ovary to maintain the secretion of progesterone during the first 3 months of preganancy
what does progesterone do
cause the uterus lining to thicken
ensure that the uterus develops and sustains the growing fetus
prevents uterine contractions and so spontatneous abortions
in the last third of pregnancy, progesterone falls and allows the mothers body to secrete what
oxytocin
in the last third of pregnancy, progesterone falls and there is a rise in…
estrogen, which causes an increase in the number of oxytocin receptors on the muscle in the uterus wall. when oxytocin binds to these receptors it causes the muscle to contract, stimulating the release of more oxytocin, contractions becoming stronger and stronger. this is positive feedback loop.
stages in fertilisation
arrival of sperm binding acrosome reaction fusion cortical reaction mitosis
what do human embryos secrete in the early stages of pregnancy
hcg, which stimulates the ovary to maintain the secretiion of progesterone so the uterus lining doesnt shed. this stops after about 12 weeks, by which point the placenta has developed and now secretes the progesterone needed to sustain the preganancy until labour. the placenta also secretes estrogen
what can th eplacenta secrete
estrogen and progesterone and hcg
when does an embryo beome a fetus
when it is 8 weeks old
what does a new fetus develop
placenta
umbilical cord
give the layers from fetus to outside
aminotic fluid placneta aminiotic sac endometrium myometrium
myometrium is
muscular wall of uterus, used during childbirth
intervillous spaces in placenta
maternal blood flows through these spaces, brought by uterine arteries and carried away by uterine veins
where does oxygenated blood flow
back to the fetus from the placenta along the umbilical vein
where does deoxygentaed blood flow
from the fetus from the placenta along the umbilical veins
what are the placental villi
small projections that give a large surface area for gas exchange and exchange of other materials. fetal blood flows through capillaries in the villi.
endometrium
lining of uterus
what exchanges across placenta to the fetus
oxygen glucose lipids water minerals vitamins antibodies hormones
what exchanges across placenta to the mother
co2
urea
hormones
water
what is in the inter villus space
maternal blood
what is chorion
forms the placental barrier, controlling what passes
what is the basement membrane’s permability
freely
adaptations of placenta capillaries carrying fetal blood
close to villus surface and has a very thin wall of single cells
what is there inside the villus
connective tissue
the nervous system consists of
thymus
spleen
transport network of lymoh nodes
describe the first line of defence
inital cells not destroyed in injury send out a chemical signal to attract attention.
large macrophages enter danger zone and kill bacteria by digesting them mercilessly.
neutrophils enter from the blood, kill everything and then themselves.
inflammation.
dendritic cell activates the specific helper t cell
neutrophils
enter from blood
kill everything and then themselves for safety a few days later
vomit deadly chemicals or eat the bacteria.
can explode and eject a toxic net of dna that trap and kill bacteria
what is inflammation
fluid from blood (dense with complement proteins) being released into the danger zone
describe (the actions of a) dendritic cell
collects samples of bacteria by ripping it into tiny parts and covering itself in it.
enters lymph nodes.
looking for a specific helper t cell that can help with this type of bacteria.
dendritic cell rubs itself against every possible t cell until it finds the one that can recognise the bacteria’s antigens
describe the second line of defence
helper t cell clones itself again and again
group1 go to the danger zone to rejuvinate macrophages.
group2 go to activate b cells. eventually making 2000 antibodies a second.
antibodies flood danger zone.
they clump bacteria together to be killed
what are b cells
protein super weapons that can make antiboies for every single type of bacteria.
end of the primary immune response
all soldier cells kill themselves to save resources except a few helper t cells which turn into memory cells.
b cell
a type of lymphocyte that, when stimulated by a particular antigen, differentiates into plasma cells that synthesize the antibodies that circulate in the blood and react with the specific antigens.
clones of plasma cells
differentiated plasma cells that secrete a specific antibody and a clone of memory cells that make the antibody on subsequent encounters.
histamine
a physiologically active amine found in plant and aminal tissue and released from mast cells as part of an allergic reaction in humans, it causes the dilation of capillaries, constriction of bronchial smooth muscle and decreased blood pressure
hybridoma
a cell hybrid produced in vitro by the fusion of a lymphocyte that produces antibodies and a myeloma tumour cell in order to produce a continuous supply of a specific antibody.
memory cell
a type of lymphocyte that is released as a specific immune response and is stored in case of a second exposure to the same antigen.
monocolonal antibodies
any of the highly specific antibodies produced in large quantities by the clones of a single hybrid cell that has been formed in the laboratory by the fusion of a b cell with a tumour cell.
t lymphocyte
a type of white blood cell that completes maturation in the thymus and that has various roles in the immune sysem, including the identification of specific foreign antigens in the body and the activation and deactivation of other immune cells.
what are antigens constructully
proteins, polysaccharides or glycoproteins
where are antigens found
on the cell wall of a bacterium, protein coat of a virus on the cell membrane of a tissue or organ transplant
as a free molecule as a toxin
where does cell mediated immunity occur
within cells
where are t lymphocytes produced
stem cells in the bone marrow
explain cell mediated immunity
t lymphocytes produced in bone marrow and then go on to the thymus gland where they are activated
each t lymphocyte has a protein receptor embedded in its membrane that has a specific shape that will bind to one type of antigen (your body will produce millions of different types of t lymphocyte)
if the t lymphocyte binds to its specific antigen it will clone itself by mitosis
some of these cells differentiate into cytotoxic t lymphocytes
these destroy host cells infected with viruses (by releasing a cytotoxin that makes holes in the membrane) because antigens from the virus are left in the host cell membrane after infection.
what is humoral immunity
physiological mechanism protects the body from pathogens and foreign substances in extracellular fluids and is part of both the innate and adaptive immune systems ( not within a cell)
explain humoral immunity
after infection by a pathogen, a macrophage engulfs the microbe and antigens from the pathogen become embedded in the cell membrane of the macrophage
a b lymphocyte is activated due to the embedded antibody binding to a complementary shaped antigen
the activated b lymphocyte then divides by mitosis forming many clones
some of these clones differentiate to become plasma cells which produce antibodies. each type of plasma cell produces one type of antibody
how many sites does each antibody have that can bind to specific seperate antigens
two sites. this allows a number of antibodies to bind many microbes to form a lattice like structure called an antibody antigen complex.
what do antibodies do
bind antigens together (agglutination forming an antibody-antigen complex)
cause the precipitation of soluble toxins rendering it harmless
bind to receptors on the surface of pathogens preventing them from binding to the cell membranes of host cells.
activate proteins which stimulate phagocytes to engulf the antibody antigen complex.
what is the latent period
the 3-14days required for the person to produce the relevant antibody.
what happens after the latent period
the concentration of antibody in the blood rises rapidly and then begins to fall when the pathogen has been killed
benefits of memory cells
the secondary immune response has a much shorter latent period and produces a much higher concentration of antibodies
do phagocytes or lymphocytes produce antibodies
lymphocytes
what process of phagocytes engulf bacteria by
endocytosis
how many antigens to antibodies bind to
only one specific antigen
where are lymphocytes stored
lymphnodes and thyroid
what are polyclonal antibodies
the production of many different antibodies from many different lymphocytes stimualted by the many antigens on a microbes surface
what does the MHC protein do
cover the antigen so the body doesnt view the macrophage as a pathogen
stages of antibody reprodution, primary response
antigen production
activation of helper t cell
activation of b lymphocytes
proliferation
what is the surface of a virus
protein coat/capsid
what is the capsid of some viruses sometimes covered by
membane taken from the plasma membrane of the host cell
how are unique surface molecules used
viruses recognize and bind to their host using molecules on the surface of the hosts cell
living organisms recognize theri own cells and cell types using surface molecules
living organisms recognize cells that are not part of the organism and also viruses by surface molecules that are not present in the organism. these moelcuels trigger the production of antibodies.
what is the ABO blood groups system based on
the presence or absence of a group of glycoproteins in the membranes of red blood cells.
what is the ABO blood group system
three different version of the glycoprotein. the O antigen is always present.
how is the A antigen made in blood groups
adding an N-acetyl-galactosamine molecule to the O antigen
how is the B antigen made in blood groups
adding galactose
what antigens are present in an o blood group
o
what antigens are present in a A blood group
O and A
what antigens are present in a B blood group
O and B
what antigens are present in a AB blood group
O, A and B
what are basophils
a type of white blood cell
what are mast cells
similar to basophils but are found in connective tissue
what is histamine secreted in response to
local infection
what does histamine do
cause the dilation of the small blood vessels in the infected area. the vessels become leaky, increasing the flow of fluid containing immune components to leave the blood vessel, resulting in both specific and non specific immune responses
what are allergies
reactions by the immune system to substances in the environment that are normally harmless, such as pollen, bee stings or specific food.
how are allergies caused
when substances in the allergens cause over production of basophils and mast cells, and therefore excrete excessive secretion of histamine.
stages in antibody production
activation of helper t cells
activation of b cells
production of plasma cells
production of memory cells
activation of t helper cells
helper t cells have antibody like receptor proteins in their plasma membrane to which one specific antigen can bind. then the helper t cell is activated, and the antigen is brought to the helper t cell by a macrophage, a type of phagocytic white blood.
activation of b cells
inactive b cells have antibodies in their plasma membrane. if these antibodies match an antigen, then the antigen binds to the antibody. an activated helper t cell with receptors for the same antigen can then bind to the b cell. the activated helper t cell sends a signal to the b cell, activating it
production of plasma cells
activated b cells start to divide by mitosis to form a clone of cells. these become very active, with a much greater volume of cytoplasm. they are then known as plasma cells. they have an extensive network of rER, used for the synthesis of large amounts of antibody which is then secreted by exocytosis.
production of memory cells
memory cells are b cells and t cells that are formed at the same time as activated helper t cells and b cells, when a disease challenges the immune system. after the activated cells adn the antibodies produced have disappeared, the memory cells persist and allow a rapid response in case the disease is encountered again, allowing long term immunity.
what is on the tips of the antibody molecule
the antigen binding sites
what is the base of the y of the antibody molecule
constant region
uses of the constant region
making a pathogen more recognizeable
preventing viruses from docking to host cells
neutralizing toxins produced by pathogens
binding to the surface of a pathogen cell an dbirsting it by causing the formation of pores.
sticking pathogens together (agglutination) so they cant enter host cells and phagocytes ingest them more easily.
what does a vaccine contain
weakened or killed forms of the pathogen. or the chemical that acts as the pathogen
describe the first test/use of a vaccine
edward jenner deliberately infected an 8 year old boy with cowpox using pus from a blister of a milkmaid with this disease. he then tried to infect the boy but he was now immune. he then tested it on 23 others including himself
what was wrong with jenner’s vaccineexperiment
the child was too young to give informed consent, and he had not done tests to find out if it had harmful side effects.
epidemiological data
study of the distribution, patterns and causes of disease in a population. can be used to help plan vaccination programmes, and prevent further spread.
what are plasma cells fused with to form hybridoma cells
tumour cells
describe pregnancy tests
urine of pregnant women contains hcg, a protein secreted by the developing embryo and later by the placenta. pregnancy tests contain monoclonal antibodies to which hcg binds. this causes a coloured band to appear, indicating that hcg was present.
what are the extracted and purified antibodies called that are produced by cultured hybridoma cells (produced by clones of the hybridoma cell)
monoclonal
how long is ther between fertilisation and a four cell embryo
about 48 hours
when the four cell embryo is fomred where is it and where is it travelling
still in the oviduct so now migrates down to the uterus (7 day journey)
when does the zona pellucida break down
once the egg cell uses up its reserves for the early embryo to grow after implantation of the blastocyst intot he endometrium lining
what does hcg do
stimulate the corpus leuteum to continue the production of progesterone and estrogen, which maintain the endometrium. it also ensures that the corpus leutum remiains until the placenta is flly established and can take over the role of progesterone and estrogen
where does fertilsiation take place
oviduct
what travels by facilitted diffusion between the mother and baby
glucose, amino acids, vitamins, minerals
urea from baby to mother
how do hormones travelf rom mother to baby
endocytosis
(and exocytosis from baby to mother
how do viruses travel from mother to baby
via receptors
What does the fetal vein carry?
oxygenated fetal blood away from the placenta
what is estrogen pollution
increasing levels of estrogne in the environemnt
what is hemolyiss
the rupture of the red blood cells membrane, leading to the release of the hemoglobin and other internal components into the surrounding fluids
the receptors on b cells bind to
antigens
what are complement proteins
a group of more than 20 proteins that are present in blood and tissue fluid. These are normally in an inactive form. Some of the complement proteins become activated when they are presented with antigens, this function is fulfilled by antibodies. When an antigen bound to an antibody is presented to a complement protein, the complement is activated and binds to the pathogen. This is called opsonisation . This then causes the pathogens to lyse or encourages phagocytosis.
what is opsonisation
the coating of a pathogen with antbodies to promote and enhance phagocytosis
what is zoonosis
transmission of a disease from animals to humans
what is histamine produced by
basophils and mast cells (wbc)
functions of histamine
dilate and increase the permeability of capillaries
what is the role of LH in spermatogenesis
stimulates the interstitial cells to release testosterone
what is the role of FSH in spermatogenesis
Stimulates meiosis I – stimulates the primary spermatocytes (2n) to produce haploid secondary spermatocytes (n).
what is the role of testosterone in spermatogenesis
Stimulates:
- Meiosis II: the formation of spermatids from secondary spermatocytes.
- Differentiation of spermatids to spermatozoa.
where is the medulla on the kindey
inbetween the outsie part (cortex) and pelvis
where is the cortex on the kidney
on the outside
just before birth, which hormonal levels change and in what order
Progesterone levels decrease, oxytocin increases, uterine contractions increase, oxytocin increases further.
list 3 features of the bowmans capsule and glmerulus that promote rapid removal of filtrate
podocytes
fenestrations
high hydrostatic pressure
explain why proteins would not be present in the filtrate in the PCT
large molecules incapable of passing the basement membrane of the capillary
two features of the PCT cells are microvilli and numerous mitcohodnria. explain why
microvilli increase surface area for reabsorption
mitochondria allow for more active transport by supplying ATP/energy
A diabetic has elevated levels of blood glucose. Suggest, using your knowledge of nephron function, why a common symptom of diabetes is the production of a larger than normal volume of urine
glucose conc of filtrate is elevated, and cannot all be reabsorbed in the PCT. water can be reabsorbed by osmosis. osmosis is less efficent and less water is absorbeddue to high solute potential.
joint cavity function
cavity contains the fluid and prevents shock damage to joint and bones
joint capsule function
produces synovial fluid
cartilidge function
reduce friction and absorb shock
explain how a pari of muscles causes movement
limbs are moved by antagonisitic pairs of muscle, as they can only provide force when contracting the extensor (tricep) muscle straightens the limb, and the antagonist flexes the limb. when one muscle contracts, the antagonist is extended to its orginal length.
how do joints limit movement
they are desiigned to allow movement to a certain extent and in certain places. the elbow is a hinge joint that allows 180 movement in one plane only
how are monoclonal antibodies used in pregannacy kits
the urine of pregnant women contains hcg, a protein secreted by the embryo and later by the placenta. preganancy test kits contain monoclonal antibodeis to which hcg binds. this causes a coloured band to appear, indicating that hcg was presen tin the urine sample, and consequently the woman is pregant.
monoclonal antibdoies are…
specific. they give an accurate/precise diagnosis.
immune response
- A macrophage engulfs the pathogen with the antigen by phagocytosis.
- The pathogen is partially digested in the lysosome.
- Macrophage presents these antigens on their membranes.
- Helper T-cells bind to the antigen on the macrophage, become activated, and then bind to the specific B cell type.
- The specific B cell type becomes activated.
- Activated B cells multiply to form clones of plasma cells and memory cells.
By the end of the proximal convoluted tubule, approximately ______ of all the water, glucose and mineral ions have been reabsorbed.
80%
immune response
A macrophage engulfs the pathogen with the antigen by phagocytosis, partially digests them and presents them on their membranes.
Helper T-cells bind to the antigen on the macrophage, become activated, and then bind to the specific B cell type.
The specific B cell type becomes activated.
Activated B cells multiply to form clones of plasma cells and memory cells.
Plasma cells secrete specific antibodies. Antibodies aid the destruction of pathogens.
Memory cells provide long-term immunity as they remain circulating in the bloodstream waiting for a secondary infection to produce more antibodies and cause a faster response.
what is the role of lh in spermatogenesis
stimulates the intertesital cells to release testosterone
FSH source
Pituitary gland
FSH role in spermatogenesis
Stimulates meiosis I – stimulates the primary spermatocytes (2n) to produce haploid secondary spermatocytes (n).
testosterone role in spermatogenesis
Stimulates:
- Meiosis II: the formation of spermatids from secondary spermatocytes.
- Differentiation of spermatids to spermatozoa.
during fertilisation what happens immediately before th penetration of the gg membrane by a sperm
- A sperm cell penetrates the follicle cells and binds to the receptors of the zona pellucida.
- The acrosomal reaction occurs when hydrolytic enzymes make a hole in the zona pellucida to reach the egg membrane.
sliding filament theory
An action potential arrives at the end of a motor neuron.
This causes the release of Ca2+ from the sarcoplasmic reticulum.
Ca2+ binds to troponin on actin fibres.
This causes troponin and tropomyosin to move, exposing the binding sites on actin for myosin heads.
what do ligaments attach together
bones
what do tendons attach together
muscle to bone
active immunity
Immunity due to the production of antibodies by the organism itself after the body’s defense mechanisms have been stimulated by antigens.
