Chapters 6 & 11 Flashcards
What are MHC?
- all nucleated cells of the body possess unique and distinctive surface molecules that identify it as self
- these self markers are called major histocompatibility complex molecules
- function as identification tags
Define immunoglobulins.
antibodies that are large and Y-shaped
How do antibodies destroy pathogens?
- agglutination
- making them more recognizable to phagocytes
- neutralising toxins of pathogens
- bursting them by forming pores
- preventing viruses from docking to host cells
How are T cells involved in the immune response?
They have antibody-like receptor proteins in their plasma membrane to which ONE SPECIFIC ANTIGEN CAN BIND
Describe an allergic reaction.
- occurs whenever non-self substance that would not normally trigger immune response enters body
- specific B cell encounters the allergen,
- it differentiates into plasma cells
- makes large amounts of antibody
- antibodies attach to mast cell
- antibodies attach to & activate mast cells
- this triggers release of histamines
- histamines can bind to membrane-bound histamine receptors & cause allergic symptoms
- histamine causes vasodilation + leaking to allow faster blood flow to area of infection
Explain the production of monoclonal antibodies.
- small mammal injected w/ one type of antigen
- antibody-producing cells removed from spleen
- plasma cells that produce antibodies are used
- myeloma/tumour cells are fused w/ plasma cells to produce hybridoma cells
- selection of hybridoma cells
- hybridoma cells are cultured/grown in tissue culture/fermenter
- hybridoma cells divide endlessly to produce desired antibody
Outline one application of monoclonal antibodies.
- detection of hCG in pregnant women
- hCG is a protein secreted by developing embryo & later by the placenta
- monoclonal antibodies for hCG are attached to the urine strip
- if hCG is present in blood, antibodies will detect this & strip will change colour
- otherwise, test strip does not change colour
Outline how the ABO blood group system is based on presence/absence of glycoproteins in membranes of red blood cells.
- these glycoproteins cause antibody production - they are antigens
- A antigen - made by adding N-acetyl-galactosamine molecule to O antigen
- B antigen made by adding galactose
- individuals w/ specific blood types may be unable to receive transfusions from other blood types
- recognizing the new blood cell as nonself
A blood: accepts A or O only
B blood: accepts B or O only
AB blood: accepts all blood types
O blood: accepts only O blood
Outline how the ABO blood group system is based on presence/absence of glycoproteins in membranes of red blood cells.
- these glycoproteins cause antibody production - they are antigens
- A antigen - made by adding N-acetyl-galactosamine molecule to O antigen
- B antigen made by adding galactose
- individuals w/ specific blood types may be unable to receive transfusions from other blood types
- recognizing the new blood cell as nonself
A blood: accepts A or O only
B blood: accepts B or O only
AB blood: accepts all blood types
O blood: accepts only O blood
What are spermatogonia?
undifferentiated germ cells
What helps spermatids to differentiate into spermatozoa?
they become associated w/ Sertoli cells
What is a primary follicle?
composed of primary oocyte and a single layer of follicle cells around it that forms after the primary oocyte becomes arrested at prophase I
What is produced at the end of oogenesis?
an ovum (haploid gamete) & one polar body
Describe the structure of an egg.
- outer layer of follicle cells (corona radiata)
- zona pellucida (jelly-like layer) - protects the egg & restricts entry of sperm
- plasma membrane
- cytoplasm - contains droplets of fat & other nutrients needed during early stages of embryo dev.
- nucleus (haploid) - contains 23 chromosomes that are passed on from mother to offspring
- 2 centrioles
- polar body
Describe the structure of sperm.
- acrosome - contains enzymes that digest zona pellucida around egg
- helical mitochondria - produces ATP by aerobic respiration to supply energy for swimming & other processes in sperm
- tail - provides propulsion that allows sperm to swim up vagina, uterus, & oviduct until it reaches the egg
- microtubules - in a 9+2 array - make the sperm tail beat from side to side to generate force that propels sperm
- protein fibers - strengthen tail
Outline the process of sex-determination.
- SRY gene is found on Y chromosome
- codes for TDF (testis determining factor), a gene regulation protein
- TDF binds to specific DNA sites to stimulate expression of genes for testis development –> MALE
- gonads develop into testes
- if SRY not present, gonads develop into ovaries –> FEMALE
Outline male sex organs.
- testes = produce sperm in seminiferous tubules + testosterone
- epididymis = sperm matures
- van deferens = sperm transferred through this duct
- seminal vesicle = mix alkaline fluid rich in fructose w/ ejaculate
- prostate gland = mixes alkaline fluid rich in enzymes/lipids/minerals –> helps sperm to swim + neutralises acidity of vagina
- urethra = tube through which sperm + urine exit
- penis = has erectile tissues which becomes enlargened & hard allowing penetration of vagina
- scrotum = holds testes at lower than core body temp.
Outline male sex organs.
- testes = produce sperm in seminiferous tubules + testosterone
- epididymis = sperm matures
- van deferens = sperm transferred through this duct
- seminal vesicle = mix alkaline fluid rich in fructose w/ ejaculate
- prostate gland = mixes alkaline fluid rich in enzymes/lipids/minerals –> helps sperm to swim + neutralises acidity of vagina
- urethra = tube through which sperm + urine exit
- penis = has erectile tissues which becomes enlargened & hard allowing penetration of vagina
- scrotum = holds testes at lower than core body temp.
Describe female sex organs.
- ovaries = egg develops in ovaries, ovaries produce estrogen/progesterone
- oviduct = pushes egg out of ovaries using cilia after ovulation + fertilisation occurs
- cervix = where male sperm will pass through + baby passes through during labour; cervix dilates to provide birth canal
- uterus = provides protection, oxygen, food, removal of waste products for fetus during pregnancy
- vagina = stimulates penis to cause ejaculation
- vulva = protects internal parts of female reproductive system
Discuss testosterone.
- produced by Leydig cells in seminiferous tubules of testes
- signals development of primary + secondary male characteristics
- triggers male sex drive
- acts on Sertoli cells in the testes and stimulates production of sperm
Discuss progesterone.
- signals dev. of female primary + secondary characteristics
- initially produced by corpus luteum in ovaries
- later produced by placenta
- helps to thicken/maintain endometrium lining
- involved in development of breast tissue during pregnancy
- prevents uterine contractions during pregnancy
Discuss estrogen.
- secreted by corpus luteum, later by placenta
- stimulates development of FSH receptors
- at high levels, it stimulates LH secretion (which stimulates ovulation)
- repairs uterus lining
- increases number of oxytocin receptors to increase uterine contractions
- fall in progesterone, rise in estrogen lead to labour/contractions
What secretes FSH & LH?
anterior pituitary gland
What secretes progesterone & estrogen?
ovaries (corpus luteum) & later on the chorion of the placenta
Examples of positive & negative feedback in menstrual cycle.
POSITIVE FEEDBACK: FSH stimulates secretion of estrogen by follicle wall, estrogen levels increase # of FSH receptors, so estrogen & FSH levels rise
NEGATIVE FEEDBACK: estrogen stimulates LH secretion; LH causes estrogen levels to fall
NEGATIVE FEEDBACK: corpus luteum secretes progesterone & estrogen, causing LH levels to fall (negative feedback since FSH & LH stimulated estrogen & progesterone secretion)
Define homeostasis.
the maintenance of stable internal conditions or environments / within narrow limits
- hormonal/nervous control
- negative feedback mechanisms
- monitored internally
What is negative feedback?
a change in one variable causes the other to change in the opposite direction
Where is leptin produced? What does it act on?
- in adipose fatty tissue cells
- leptin acts on receptor sites of hypothalamus
Outline how melatonin acts to control circadian rhythms.
- ganglion cells in retina detect differences in light/dark
- send impulse to supra-chiasmatic nuclei (SCN) in hypothalamus
- neurons in SCN control secretion of melatonin by pineal gland
- melatonin acts on hypothalamus –> sleepiness
- this hormone is removed by liver
How does thyroxin increase body temperature?
- increases metabolic rate
- uncoupled cell respiration in brown adipose tissue
- heat generation by shivering
- hypothalamus in brain detects temp changes
Why is iodine important for synthesis of thyroxin?
- thyroxin molecule contains 4 atoms of iodine
- prolonged deficiency of iodine in diet prevents synthesis of thyroxin
How is the body cooled?
- less thyroxin is secreted from thyroid gland
- release of sweat by sweat glands
- evaporation of water cools body
- heat is transferred by blood
- transfer of heat from body core in blood to surface via vasodilation of skin blood vessels
Which 2 organs are responsible for maintaining blood pH?
- lungs - by exhaling CO2
- kidney
Distinguish b/w internal & external fertilisation.
- external –> water required, timing is critical, lots of energy used, energy goes into producing many eggs, no parental care of offspring
- internal –> water balanced in a dry environment, fewer eggs - protection for egg/embryo; complex organs & cooperative behaviour; parental care of offspring is high
Outline features of steroid hormones.
- derived from cholesterol
- progesterone, estrogen, testosterone
FSH & LH ARE NOT STEROID HORMONES
Distinguish b/w Type I & Type II diabetes.
TYPE I:
- childhood, genetics
- immune system destroys beta cells in pancreas so amount of insulin secreted is insufficient
- high levels of glucose in bloodstream
- treated by regular insulin injections
TYPE II:
- occurs later in life due to lifestyle factors
- beta cells become desensitised to glucose levels, preventing release of insulin
- insulin injections not enough
- diet must be healthy
- risk factors include diet rich in fat, low in fiber, obesity, lack of exercise
Distinguish b/w Type I & Type II diabetes.
TYPE I:
- childhood, genetics
- immune system destroys beta cells in pancreas so amount of insulin secreted is insufficient
- high levels of glucose in bloodstream
- treated by regular insulin injections
TYPE II:
- occurs later in life due to lifestyle factors
- beta cells become desensitised to glucose levels, preventing release of insulin
- insulin injections not enough
- diet must be healthy
- risk factors include diet rich in fat, low in fiber, obesity, lack of exercise
What is the function of circular muscle in peristalsis?
prevents backward movement of food
What is the function of longitudinal muscle in peristalsis?
moves bolus food along the gut
Function of lipase in digestion.
breaks down LIPIDS into FATTY ACIDS & GLYCEROL
Define absorption.
the taking in of digested food substances as well as minerals and vitamins from the lumen of the small intestine into the blood
Adaptations of the villi of small intestine.
- goblet cells produce mucus
- epithelial cells is where absorption takes place
- capillary network & lacteal carry absorbed nutrients away from intestine
- microvilli (hair-like folds on surface of epithelial cells) on the villi further increase SA
- it is the mucosa layer of small intestine that contains villi
How are cholesterol / fats absorbed?
- absorbed into lacteal of villi
- carried in lipoprotein complexes in the blood
Outline digestion of starch.
- amylase breaks 1,4 bonds in amylose to produce MALTOSE
- it cannot BREAK the 1,6 bonds in amylopectin
- these segments form dextrins
- maltase & dextrinase break down maltose + dextrins into glucose
- membranes in microvilli contain protein pumps that cause absorption of glucose
- blood carrying glucose + products of digestion flows through villus capillaries to venules in submucosa of wall of small intestine
- this then passes along the hepatic portal vein into liver where it is stored as GLYCOGEN
Function of liver.
- stores glycogen + secretes bile into small intestine
- bile creates favorable pH for enzymes
- bile salts emulsify fats
Function of gall bladder
- STORES bile, while liver secretes bile
Is the small intestine alkaline or acidic?
ALKALINE
example of simple diffusion
fatty acids
example of facilitated diffusion
fructose
example of co-transporter proteins (Active transport)
glucose
examples of active transport
ions, amino acids
example of endocytosis
cholesterol in lipoprotein complexes
Characteristic of substance that can undergo simple diffusion.
- HYDROPHOBIC
- NON-POLAR
Function of vagus nerve.
slows down heart rate
Function of sympathetic nerve.
accelerates heart rate
Outline how the heart rate is controlled.
- SA node in right atrium acts as pacemaker
- recieves electrical signals from medulla to increase / decrease rate of contraction
- from medulla to SA node signal passes through nerves
- sends signal down both atria, down septum to the ventricles, causing both to contract at faster rate
- epinephrine is hormone produced by adrenal gland –> increases heart rate during fight or flight
What is systemic circulation?
Pumping of blood around the body
What is the SA node?
group of specialised muscle tissue
List some components of blood
- plasma / water
- dissolved gases
- red blood cells (erythrocytes)
- white blood cells (leuokocytes)
- lymphocytes + phagocytes
- platelets
- hormones
- amino acids
- antibodies
- salts, minerals, ions
Describe structure of arteries.
- pressure is high
- thick, muscular walls w/ collagen / elastic fibres to withstand pressure
- elastic fibres recoil in response to ventricular contraction
- muscle / elastic fibres help maintain pressure b/w heart beats
- propel blood towards capillary beds (AWAY FROM HEART)
- thick, small lumen for high pressure
- no valves
- smooth endothelium for efficient transport / reduced friction
Describe structure of capillaries.
- 1 cell thick (Epithelium)
- allow for short diffusion distance for exchange of oxygen (gas exchange)
- nutrients move into tissues
- hormones leave capillaries in target tissues & attach to receptors on cell
- capillaries have pores to allow lymphocytes to exit & increase permeability
- extensive branching of capillaries increases SA
- small diameter allows them to fit in b/w cells
Describe structure of veins.
- low pressure in veins
- large lumen of veins –> less resistance to blood flow
- elastic muscles
- valves to prevent backflow
- carry blood TOWARDS heart
- thin walls allow skeletal muscles to exert pressure on veins
- thin outer layer of elastic muscle provides structural support
Describe structure of veins.
- low pressure in veins
- large lumen of veins –> less resistance to blood flow
- elastic muscles
- valves to prevent backflow
- carry blood TOWARDS heart
- thin walls allow skeletal muscles to exert pressure on veins
- thin outer layer of elastic muscle provides structural support
Examples of non-specific immunity
- mucous membranes
- skin –> sebaceous glands secrete lactic acid
- inflammatory response –> swelling + heat
- blood vessel dilation –> increase in capillary permeability
- low pH of skin / stomach
- cilia in trachea push out pathogens in mucous
- phagocytosis
Which one is soluble - fibrin or fibrinogen?
- fibrinogen is SOLUBLE
- fibrin is INSOLUBLE
List some named proteins.
- clotting factors
- fibrin
- thrombin (protease)
- antibodies
- plasma cells
- memory cells
- immunoglobulins
- enzymes in phagocytic white blood cells
Outline the functions of antibiotics.
- inhibit growth of micoorganisms
- bacteria/prokaryotic processes blocked but not processes in eukaryotes
- block metabolic pathways (translation, cell wall formation, DNA replication)
- DO NOT PROTECT AGAINST viruses
- antibiotics fail to protect against bacteria if they have resistance
- do not affect eukaryotic cells
Why don’t antibiotics protect against viruses?
- they have no metabolism
- they are non-living
Define ventilation.
the exchange of gases b/w lungs & air
inspiration
- external intercostal muscles contract
- diaphragm contracts (becomes flatter)
- ribcage moves UP & OUT
- vol of lungs ICNREASEs, PRESSURE DECREASE
expiration
- external intercostal muscles relax
- internal intercostal muscles contract
- diaphragm relaxes
- ribcage moves DOWN & IN
- vol of lungs DECREASES, PRESSURE increases
Distinguish b/w ventilation, gas exchange, aerobic cell respiration.
- ventilation is moving air into and out of lungs/inhalation and exhalation;
- involves (respiratory) muscle activity;
- gas exchange involves movement of carbon dioxide and oxygen;
- between alveoli and blood (in capillaries)
- cell respiration is the release of energy from organic molecules/glucose;
- (aerobic) cell respiration occurs in mitochondria;
Example of antagonistic muscles
diaphragm & abdominal muscles
What is myelin sheath composed of?
cholesterol / fatty acids that allows for saltatory conduction
Define nerve impulses
action potentials propagated along axons of neurons
Define local currents
movement of sodium ions along axon, causing depolarisation followed by repolarisation
Why is myelination important?
- it increases propagation speed
- allows for saltatory conduction
- permits jumping from node to node
- myelin around neuron insulates axon
Define synapse
junction b/w neurons OR b/w neurons & receptor / effector cells
Define resting potential
the electrical potential difference across the plasma membrane when the cell is in a non-excited state
What types of antigens AND antibodies are found in people with blood type B?
- B antigens on their red blood cells
- A antibodies in plasma
