topic eleven Flashcards
antigen define
any moelcule that can trigger an immune response leading to the generation of antibodies
all red blood cells have antigen ___ ontheir surface
H
what is added to antigen H for blood group a
For blood group A, N-acetylgalactosamine is added,
what is added to antigen H for blood group b
galactose is added
The immune system forms antibodies against whichever ABO blood group antigens are ??? found on the individual’s RBCs
not
what is agglutination
hemolysis and potentially death
The transfusion of type A blood to a person who has type O blood would result in:
The recipient’s anti-A antibodies clumping the donated red blood cells
how does the body deal with an infection
- The antigen is quickly ingested (via phagocytosis) by macrophages and B cells. Both process the antigen and present it on their surface.
- The macrophage (now called antigen-presenting cell) interacts with a helper T cell. This activates the helper T cell.
- The activated helper T cell interacts with the B cell that has the antigen on its surface (shown in step 2 in the diagram) and activates it. The activated B cell rapidly divides by mitosis to form clones of plasma cells and memory cells. The plasma cells possess lots of rough endoplasmic reticulum and a well-developed Golgi apparatus making them well-suited for producing antibodies (of one specific type) against the antigen.
- The memory B cells, produced in much smaller amounts than the plasma cells, stay in the body for years after both plasma cells and antibodies have disappeared. If an infection with the same antigen recurs, the memory B cells quickly divide to form plasma cells (as well as a new set of memory cells), which secrete antibodies against this specific infection. Memory cells provide long-term immunity to diseases.
diagram of an antibody
what is the variable tregion of an antibody
highly specific to a particualar antigen
how can pathogens be inactivated
neutralisation
agglutination
complement
what is neutralisation inactivation of pathogens
binds to pathogen to block key biological activity eg inhibits virus entry into host cells
agglutination inactivation of pathogens
causes clumping of pathogens so phagocytes can engluf a number of pathogens at once
opsonisation
Opsonisation is the coating of a pathogen with antibodies to promote and enhance phagocytosis.
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.
When an antigen bound to an antibody is presented to a complement protein,
the complement is activated and binds to the pathogen. this then causes the pathogens to lyse or encourages phagocytosis
antigens are anything that
triggers an immune repsonse
antibodies are produced by
plasma cells (originally B cells)
what is the primary response
The immune response triggered on the first encounter of the body with an antigen
waht is produced following the primary response
memory cells are so that if there is another infection with the same patogen, your body can react quickly
vaccinations
inject an attenuated (weakened) form of the pathogen, or a toxin that is produced by the pathogen, into the body. Vaccines contain antigens that trigger immunity but do not cause the disease.
what causes smallpox
Variola major and V. minor
what is zoonoisis
where pathogens can cross the species barrier eg ebola in monkeys eventually also in humans
epidemiology
the study of the distribution, patterns and causes of diseases in a population. By studying the spread, patterns and causes of diseases, predictions can be made and preventative measures undertaken.
allergen
the study of the distribution, patterns and causes of diseases in a population. By studying the spread, patterns and causes of diseases, predictions can be made and preventative measures undertaken.
what produces hitamine
basophils and mast cells (both are types of white blood cells) found in the connective tissues
one of the functions of histamine is to
dilate and increasae the permeability of capillaries. this enables wbc such as mast cells and some proteins to invade the affected tissues and engage the allergens
Immune response after an allergen has entered the body.
uses of monocolonal antibodies
cancer tests
preganancy tests
They are also used as therapeutic agents in rheumatoid arthritis, B cell leukaemia and non-Hodgkin’s lymphoma. Georges Köhler, César Milstein and Niels Kaj Jerne published this technique in 1975 and shared the Nobel Prize in Physiology or Medicine in 1984 for the discovery.
eptitope
a short amino acid sequence on the antigen that the antibody is able to recognise.
what cells are fused to make a hybridoma
tumour and antibody producing plasma cell
what cell makes monocolonal antibodies
hybridoma cells
how are monocolonal antibodies produced
A mouse is injected with an antigen X (1) for which a monoclonal antibody is needed. Once the mouse’s spleen starts to produce polyclonal antibodies in its plasma B cells, the spleen is removed (3) and is fused with myeloma cells (an immortalised, cancerous cell line; these myeloma cells have lost certain abilities, such as the ability to replicate their own DNA). Cells are cultured on a medium that is selective for fused (hybridoma) cells (4). Unfused myeloma cells cannot grow because they cannot replicate their DNA (2). The hybridoma cells can replicate their own DNA (5). Each hybridoma cell is then cultured separately and screened. Once it is confirmed that a certain hybridoma is producing the right antibody, it is cultured indefinitely and monoclonal antibodies are harvested from it.
how do preganancy tests work
detects presence of HCG
(a) The test stick is dipped into the woman’s urine.
(b) The test stick contains anti-HCG antibodies with attached blue dye. If HCG is present it will bind to the antibodies.
(c) Monoclonal antibodies are attached to the membrane within a window on the test stick. If HCG is present in the urine and bound to the anti-HCG antibodies, the HCG will also bind to the monoclonal antibodies as it travels up the stick. This complex also contains the blue dye which shows a blue line within the window. This blue line indicates the presence of HCG and therefore a positive result.
(d) The urine continues to move up the test stick. As it reaches the top there is another line of monoclonal antibodies. These antibodies are a complementary shape to the anti-HCG. The anti-HCG is always present therefore this line will always turn blue as a result of the blue dye. This line acts as a control and allows the user to check if the test is working. This line does not indicate whether the user is pregnant or not.
Monoclonal antibodies are produced by fusion between:
Mouse spleen B cells and myeloma cells
where are muscles attached in insects
to the exoskeleton
what is the exoskeleton
an external structure usually made of chitin (a modified polysaccharide containing nitrogen) that protects the softer body parts of these animals
antagonistic meaning
when one muscle contracts, the other relaxes
Hind limb of a cockroach diagram
What is the role of bones and the exoskeleton in organisms?
To provide anchorage for muscles and act as levers
what is bone amde of
many material sincludign calcium phosphate, collagen and elastic protein
what are synovial joints
joints that possess a synovial cavity between the two bones. This cavity is filled with synovial fluid that reduces friction at the joint, allowing bones to move freely. Synovial joints allow a high range of motion. However, synovial joints allow certain movement but not others.
what is a dislocation
an injury to a joint where the bone ends are forced from their normal positions
labelled knee joint
labelled hip joint
labelled elbow joint
what should joint annotations conatain
Annotations should include cartilage, synovial fluid, joint capsule, named bones and named antagonistic muscles.
what type of joint is th ehip
It is a ball and socket joint that can flex and extend in many directions.
The cell membrane of a striated muscle fibre cell is known as
the sarcolemma
Muscle fibres consist of many myofibrils and have a lot of endoplasmic reticula; however, in muscles, this is called
the sarcoplasmic reticulum
waht does the sarcoplasmic reticulim store
calcium
labelled sarcomere
sarcomeres are found in
skeletal and cardiac muscles
sliding filament theory
the actin and myosin filaments slide over each other to make the muscle shorter: actin slides over myosin moving inwards towards the centre of the sarcomere. This makes the length of all the sarcomeres shorten, thus the entire muscle becomes shorter.
steps in sarcomere contraction
ATP attaches to myosin head.
Myosin head detaches from its binding site on actin filament.
ATP splits into ADP and P.
Myosin head cocks to an angle.
Myosin head attaches to binding site on actin filament.
As ADP and P detach, the myosin head changes position and pushes the actin filament along – this is known as the power stroke.
The myosin head detaches from the actin filament and reattaches to the next binding site, repeating the cycle. This achieves ‘movement’.
When a muscle receives a neuronal impulse to contract, the following happens:
Calcium ions are released from the sarcoplasmic reticulum.
Calcium ions bind to troponin, which forces tropomyosin to move.
This move exposes the myosin-binding sites on the actin.
Myosin heads can now make a cross bridge and pivoting the actin filaments towards the centre of the sarcomere.
animals excrete their nitrogenpus waste in three mainf orms:
urea, uric acid and ammonia
osooregualtors
organisms that are able to keep or regulate the solute concentration of their body fluids above or below that of their external environment. These organisms have the ability to control the osmolarity of their tissues within very narrow limits. Changes in their environment generally have no effect on or cause only small fluctuations in their internal solute concentration. Examples of osmoregulators include humans and birds.
osmoconfromers
Osmoconformers are marine organisms that actively or passively maintain an internal environment that is isosmotic to their external environment. This means that the solute concentration of their body fluid is the same as the solute concentration of the external medium in which the organisms live. These organisms cannot regulate the solutes of their body fluids at a concentration that is different from that of the external medium. Examples of osmoconformers include sea stars, molluscs, marine crabs, jellyfish and other marine invertebrates.
what can happen if someone is overhydrated
The consequence of overhydration is the swelling of body cells. This creates a very dangerous situation, as swollen cells in the brain lead to intracranial pressure. As this pressure increases, the blood flow to the brain can be interrupted, leading to dysfunction in the central nervous system, seizures, coma or even death. Additionally, consequences such as nausea and vomiting, changes in mental state (confusion or disorientation), muscle weakness or cramps, as well as unconsciousness may occur.
what is osmoregualtion
the maintenance by an organism of an internal balance between water and dissolved materials, regardless of environmental conditions. It includes the control of the water balance of the blood, tissue or cytoplasm of a living organism.
labelled kidney
why is glucose reabsobred
for metabolic proccesses
where is the carbon dioxide higheer, renal artery or renal vein
renal artery
You should be able to annotate the following parts on nephron diagrams:
glomerulus, Bowman’s capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule and the collecting duct.
bowmans capsule function
Highly porous wall which collects the filtrate
glomerulus function
Knot-like capillary bed where high-pressure filtration takes place
pct 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
dct 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 function
Brings blood from the renal artery
labelled bowmans capsule
labelled podocyte
Proximal convoluted tubule and the reabsorption process.
what happens when osmolarity is back to normal
ADH secretion stops and the water channels are removed from the membrane and reform as vesicles. The collecting duct is then impermeable to water and the filtrate flowing through it is lost as urine without further water absorption.
what is hemodialysis
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. 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.
what is the malpighian tubule system
in insects carries out osmoregulation and removal of nitrogenous wastes.
how do spermatogonia develop into sperm
Spermatogonia grow into larger cells called primary spermatocytes (2n). Each primary spermatocyte carries out the first division of meiosis to produce two secondary spermatocytes (n).
Secondary spermatocytes carry out the second division of meiosis to produce two spermatids (n).
Spermatids become associated with nurse cells, called Sertoli cells, which help the spermatids to develop into spermatozoa (n) or sperm. This is an example of cell differentiation. Sertoli cells provide nurture and support. The function of Sertoli cells is to nourish the developing sperm cells through the stages of spermatogenesis.
Sperm detach from Sertoli cells and are eventually carried out of the testis by the fluid in the centre of the seminiferous tubule.
the process of oogenesis
At puberty, FSH (follicle stimulating hormone) begins to be produced and causes some follicles to develop each month. This allows the oocyte to complete the first meiotic division.
The first meiotic division forms two cells. The smaller of the two cells is the polar body which eventually degenerates. The larger cell becomes a secondary oocyte which enters meiosis II. Meiosis II is halted at metaphase II if fertilisation does not occur.
If fertilisation does occur, meiosis II continues and a second polar body and a ovum are produced.
labelled spermatogenesis
labelled oogenesis
labelled sperm
labelled egg
blastocyst diagram
human placenta labelled
which hormones induce pain
The fetus signals to the placenta to stop producing progesterone. This triggers the secretion of oxytocin, which is produced by the posterior lobe of the pituitary gland and by the fetus. While the progesterone level drops prior to birth, the estrogen level continues to rise and induces the development of oxytocin receptors on the muscles of the uterine wall. This increases the responsiveness of the uterus to oxytocin.
structure of trna
Aminoacylation of a tRNA molecule.
tRNA with attached amino acid.
