Final Exam Flashcards
What is normal plasma pH?
7.4
What can disturbance of pH homeostasis cause?
-Disturbance of protein shape
-Disturbance of K+ levels
-Effects on excitable tissues
What is the largest determinant of pH?
Metabolic production of CO2 is the largest source of excess H+
What is a buffer system?
Mixture of 2 compounds that can remove free H+ as needed
What is the most important extracellular buffer?
Bicarbonate
What is the most important intracellular buffer?
Proteins
What are the 4 buffer systems in our body?
- Bicarbonate
- Proteins
- Phosphate
- Ammonia
What is the equation for pH?
pH = 6.1 + log (HCO3- / CO2)
How does respiratory compensation work as a homeostatic mechanism for pH?
Can only fix metabolic pH problems by controlling rate of CO2 removal
How does renal compensation work as a homeostatic mechanism for pH?
-Slow but most powerful pH regulator
-Usually secrete H+ to make urine more acidic
-Usually absorb HCO3-
What are intercalated cells?
Cells in distal nephron that play key role in renal pH compensation
What are Type A intercalated cells?
-Active when in acidosis
-Secretes H+ into filtrate & Absorbs HCO3- into blood
How do Type A intercalated cells secrete H+ into filtrate?
Uses H+/K+ exchanger –> acidosis often leaded to hyperkalemia (high K+ in blood)
What are Type B intercalated cells?
Active when in alkalosis
-Absorbs H+ into the blood & Secretes HCO3- into filtrate
How do Type B intercalated cells absorb H+ into blood?
Uses H+/K+ exchanger –> alkalosis often leads to hypokalemia (low K+ in blood)
What are the types of pH disturbance?
-Respiratory acidosis or alkalosis= underlying cause is a change in PCO2
-Any other pH disturbance is referred to as metabolic
What is respiratory acidosis?
-Due to hypoventilation
-Respiratory system is the problem, all compensation is renal
What is metabolic acidosis?
-Due to addition of acids or removal of HCO3-
-Compensation by lungs (rapid)
-Renal compensation (slow)
What is respiratory alkalosis?
-Due to hyperventilation
-Respiratory system is the problem, all compensation is renal
What is metabolic alkalosis?
-Due to removal of acids or addition of HCO3-
-Compensation by lungs (rapid)
-Renal compensation (slow)
What are the hypothalamic control centers for food intake?
- Feeding center: tonically active
- Satiety center: inhibits feeding center
What is Neuropeptide Y (NPY)?
Neurotransmitter in the brain that is main signal responsible for increased food intake/ hunger
What is Ghrelin?
Hormone secreted by stomach when empty to stimulate an increase in food intake
What is leptin?
Hormone secreted by adipocytes when fat stores increase in order to decrease food intake
What is CCK & GLP-1?
Hormones secreted by the duodenum in response to fats and carbs in chyme to decrease food intake
What is the fed (absorptive) state?
Absorbing nutrients at GI tract
What are the characteristics of the fed state?
-Mainly anabolic (storage/synthesis)
-Glycolysis is main energy source
-Protein synthesis
What is glycogenesis? What state does this occur in?
Glucose is converted to glycogen in liver & muscle; occurs during fed state
What is lipogenesis? What state does this occur in?
Fat synthesis in adipocytes; occurs in fed state
What does lipogenesis use?
-Glycerol & fatty acids
-Converted excess carbohydrates & amino acids
What is the fasted (post-absorptive) state?
No absorption occurring at GI tract
What are the characteristics of the fasted state?
-Mainly catabolic (breakdown)
-Maintain blood glucose
What is glycogenolysis? What state does it occur in?
Glycogen is converted into glucose in the liver and causes glucose release; occurs in fasted state
What is gluconeogenesis? What state does it occur in?
Liver produces glucose from glycerol (adipocytes) & pyruvate, lactate, & AAs (skeletal muscle); occurs in fasted state
Why do fats become a major energy source in the fasted state?
Fats have higher energy content than glycogen, but are slower to metabolize
What is Lipolysis?
Triglycerides are converted into glycerol + free fatty acids
- glycerol used in glycolysis
- fatty acids enters Krebs cycle as acetyl CoA
What happens during extended fasting?
-Body proteins used heavily as source of AA
-Brain uses ketone bodies produced from FFA in liver
What ratio regulates metabolism?
Inverse ratio of insulin-to-glucagon
Why is insulin dominant in the fed state?
High blood glucose stimulates pancreatic beta cells to secrete insulin
What happens when insulin is secreted during the fed state?
-Incr. glucose uptake
-Incr. glycolysis
-Incr. glycogenesis
-Incr. lipogenesis
-Incr. protein synthesis
-Decr. blood glucose
What is the mechanism for insulin uptake in the fasted state in adipose tissue and resting skeletal muscle?
No insulin –> no GLUT4 transporters in membrane –> no glucose entry
What is the mechanism for insulin uptake in the fed state in adipose tissue and resting skeletal muscle?
Insulin binds to receptor –> GLUT4 transporters in membrane –> glucose allowed to enter cell
How does insulin indirectly alter glucose transport in the liver?
GLUT2 transporters always present in hepatocyte membrane
What is the mechanism for insulin uptake in the fasted state in the liver?
Glycogenolysis –> high glucose inside the cell –> glucose diffuses out of the cell
What is the mechanism for insulin uptake in the fed state in the liver?
Insulin activates glucokinase in the cell that phosphorylates glucose to glucose 6-phosphate to keep glucose low inside the cell so that glucose will diffuse into the cell
What are the feedfoward mechanisms influencing insulin secretion?
-Carbohydrates in gut stimulate incretins (GIP & GLP-1) to increase insulin
-Stretch of the gut incr. parasympathetic input which incr. insulin
How is glucagon dominant in fasted state?
-Low blood glucose stimulates pancreatic alpha cells to secrete glucagon:
- incr. glycogenolysis in liver
- incr. glucogenesis in liver
to incr. blood glucose
What are 2 other hormones that help increase blood glucose?
Cortisol & Epinephrine
Why are humans homeothermic?
We regulate internal temperature within a narrow range
What happens when our temperature is too high?
Hyperthermia = denature enzymes
What happens when our temperature is too low?
Hypothermia = chemical reactions too slow
What is the equation for heat gain and loss being balanced at equilibrium?
External heat input + internal heat production = heat loss
What are the mechanisms of heat exchange?
- Radiation (gain or loss)
- Conduction (gain or loss)
- Convection (gain or loss)
- Evaporation (loss)
What is radiation?
Warm surfaces emit and absorb electromagnetic waves that travel through space
What is conduction?
-Heat transmission by contact
-Transferred by thermal molecular motion
What is convection?
Heat transmission by bulk flow of air or water
What is evaporative heat loss?
From skin and respiratory tract
How does normal metabolism generate internal heat production?
Only ~25% of nutrient energy is captured as cellular work - the rest is “wasted” as heat, but can be used to maintain body temp
How does voluntary muscle contraction generate internal heat production?
Can be used for behavioral thermoregulation
What is shivering thermogenesis?
Involuntary tremors in skeletal muscles
What is non-shivering thermogenesis?
-Mitochondrial uncoupling: energy from electron transport system released as heat in brown adipose tissue
Where are the sensors for the homeostatic reflex of temperature regulation?
-Central thermoreceptors (hypothalamus)
-Peripheral thermoreceptors (skin)
What is the thermoneutral zone?
Range of environmental temperatures in which thermoregulation requires only vascular adjustments
What is the response to decreased temperature by sympathetic adrenergic response?
Cutaneous vasoconstriction decreases convective flow from interior to skin to decrease skin temperature to decrease heat loss
What is the response to decreased temperature by somatic motor neurons?
Shivering thermogenesis
What is the response to increased temperature through active cutaneous vasodilation?
Increase in heat loss at skin due to sympathetic cholinergic neurons
What is the response to increased temperature by sweat glands secreting sweat?
-Sympathetic cholinergic neurons
-Energetically expensive: main reason for incr. in metabolic rate above thermoneutral zone
-Evaporative cooling causes incr. net heat loss
What causes an increased set point in the hypothalamus?
Fever
What causes a decreased set point in the hypothalamus?
Hot flashes
What is the function of the digestive system?
Move materials from external to internal environment
What is the enteric nervous system?
Neurons in GI wall that control motility & secretion
What is the short reflex in the digestive system?
Originates within ENS and is integrated there without input from CNS
What is the long reflex in the digestive system?
Integrated in the CNS from sensory input from ENS and Autonomic output to ENS
What is amylase? Where is it found?
Amylase is found in saliva and pancreas and digests polysaccharides to disaccharides
What is the disaccharidases? Where is it found?
Disaccharidases are found on the membrane of cells in the small intestine and they digest disaccharides to monosaccharides
What kind of energy does a GLUT use?
Facilitated diffusion
What kind of energy does a SGLT use?
Secondary active transport
How are glucose & galactose absorbed?
-Apical entry - SGLT
-Basolateral exit - GLUT2
How is fructose absorbed?
-Apical entry - GLUT5
-Basolateral exit - GLUT2
What are endopeptidases?
Break peptide bonds in interior or protein/peptide i
What is pepsin & where is it found?
Endopeptidase; in stomach
What is trypsin & where is it found?
Endopeptidase; in small intestine
What is an exopeptidase?
Remove amino acid at the end
What does carboxypeptidase do?
Removes from carboxy-terminal end
What does aminopeptidase do?
Removes from amino-terminal end
How are free amino acids absorbed?
Most by cotransport with Na+
How are di- and tripeptides absorped?
-Cotransport with H+
-Most are digested inside the cell to free amino acids
What do bile salts in bile do?
Emulsify fats to break into smaller droplets to incr. surface area for enzymatic digestion
What does the lipase do?
Digests triglycerides into monoglyceride + 2 free fatty acids
What does the colipase do?
Protein cofactor that displaces part of the bile salt coating to give lipase access to fats inside
What do the products of lipid digestion do?
Assemble with bile salts & phospholipids into a micelle
What happens in the cephalic phase of digestion?
Sight, smell, taste, & thought of food signal the medulla to incr. PSNS input to incr. salivary gland secretion & incr. secretion and motility throughout digestive system
What is the cephalic phase?
Feedforward response to anticipation of food
What is the gastric phase?
Increase in gastric secretion & motility stimulated by entry into stomach of chyme
What happens during the gastric phase?
-Distention & presence of peptides/amino acids in lumen incr. gastrin secretion by G cells, incr. HCl secretion by parietal cells, and incr. pepsinogen secretion by chief cells
What does acid in the lumen during the gastric phase do?
Acts as negative feedback to incr. somatostatin from D cells and decr. secretion by G cells, parietal cells, and chief cells
What is the intestinal phase?
Changes in secretion & motility stimulated by entry of chyme into duodenum
What does acid do during the intestinal phase?
acid incr. secretin secretion that incr., pancreatic bicarbonate secretion
What do fat & proteins do during the intestinal phase?
fats & proteins incr. CCK which incr. pancreatic enzyme secretion & bile release by gallbladder
What do carbohydrates do during the intestinal phase?
Carbohydrates incr. incretins which increase insulin secretion
What is homeostasis?
The ability of the body to maintain a relatively constant internal environment.
What are examples of regulated variables?
Temperature, pH, ion concentrations, nutrient availability, etc.
What are the parts of a control system that maintains homeostasis?
Stimulus, Sensor, Integrating center, Target/Effector
What is the feedforward control strategy?
Occurs in anticipation of change
What is the feedback control strategy and what types are there?
Feedback occurs in response to change. Negative feedback restores normal value and positive feedback enhances change.
Why do compartments maintain different concentrations of each solute?
Resulting gradients can be used as energy source.
What are the 3 types of transport mechanisms? Describe each and what molecules they transport.
- Simple Diffusion: diffusion across lipid bilayer (nonpolar molecules: gases, lipids, etc)
- Protein-mediated transport: (small polar molecules: glucose, amino acids, water)
- Vesicular transport: (very large molecules: proteins)
What is a channel protein? What do they transport?
Channel proteins form continuous connection between ICF & ECF to transport ions and water.
What are the types of channel proteins?
- Leakage (open)
- Gated (closed)
- Chemically-gated
- Mechanically- gated
- Voltage- gated
What are the characteristics of channel proteins?
-can only mediate passive transport
-rate depends on gradient & number of channels
What is a carrier protein?
Bind to molecules and change shape to carry them across a membrane.
What are the characteristics of carrier proteins?
-Never form continuous connection between ICF & ECF (“revolving door”)
-slower than channel proteins
-can move larger molecules
-can use passive or active transport to move across gradients
What are the types of carrier proteins?
- Uniporter: one kind of molecule
- Cotransporter: two or more kinds of molecules
- Symporter: in same direction
- Antiporter: in opposite direction (exchanger)
What is primary active transport? What is an example?
Binds ATP directly. Ex: Na/K ATPase
What is secondary active transport? What is an example?
Uses ATP indirectly. Uses energy stored in a concentration gradient to move something else against its concentration gradient. Ex: Na/glucose-linked transporter
What is the electrical potential difference (Vm)?
Voltage of stored energy
How are ions subject to chemical (diffusional) force?
Diffusion down concentration (chemical) gradient
How are ions subject to electrical force?
From interaction of ionic charge with charge separation across membrane (electrical gradient)
-opposites attract
Electrical & chemical forces are _____ & ______
equal & opposite
What is the membrane potential? What does it arise from?
At the resting membrane potential, no ion species is at its equilibrium potential. Membrane potential (Vm) arises from weighted contributions of each ion’s Ex based on:
1. Ion’s concentration gradient
2. Ion’s permeability
How are electrical signals produced?
Gated channel opens or closes which changes an ion’s membrane permeability and the resting membrane potential.
What is tonic control?
Signal is always present, but changes in intenstiy
What is antagonistic control?
Opposing signals send parameter in opposite directions
What is the HPG axis? What is an example?
Hypothalamic-pituitary-gonadal axis
GnRH (hypothalamic) –> LH/FSH (pituitary) –> sex hormones (gonads)
What is the HPT axis? What is an example?
Hypothalmic-pituitary-thyroid axis
TRH (hypothalamic) –> TSH (pituitary) –> thyroid hormones (thryoid)
What is the HPA axis? What is an example?
Hypothalamic-pituitary-adrenal axis
CRH (hypothalamic) –> ACTH (pituitary) –> cortisol (adrenal cortex)
What is long-loop feedback?
Peripheral gland secretion inhibits secretion by hypothalamus & anterior pituitary
What is short-loop feedback?
Anterior pituitary secretion inhibits secretion by hypothalamus
What is a primary pathology?
Dysfunction of peripheral endocrine gland
What is secondary pathology?
Dysfunction of pituitary gland
What is tertiary pathology?
Dysfunction of hypothalamus
What are the functional regions of a neuron?
Input region: dendrites & soma
Integrative/trigger zone: Initial segment of axon
Conductive region: Axon body
Output region: axon terminal
What are the 2 types of electrical signals?
- Graded potentials
- Action potentials
What is the purpose of a graded signal?
Local signals to carry information from input region to trigger zone.
What is the purpose of an action potential?
Used for long-distance signals to carry information from trigger zone to axon terminal.
What are the characteristics of graded potentials?
-Originate in input region due to opening of gated channels
-Decrease in amplitude as they travel
-Carry information to integrative zone
-Can be excitatory or inhibitory
What does an excitatory signal do?
Depolarize the cell to make it easier to produce an action potential.
What does an inhibitory signal do?
Hyperpolarize the cell to make it harder to produce an action potential.
What is a receptor potential? Is it excitatory or inhibitory?
A receptor potential is a graded potential in the input region of a sensory neuron.
-Always excitatory
What is an EPSP?
An excitatory postsynaptic potential is a graded potential in the input region of an interneuron and motor neuron.
What is an IPSP?
An inhibitory postsynaptic potential is a graded potential in the input region of an interneuron or motor neuron.
What is an EPP? Is it excitatory or inhibitory?
An end-plate potential is an excitatory graded potential in the input region of a skeletal muscle.
How are amplitude & duration graded in a graded potential?
-Directly proportional to triggering stimulus
-Conveys information about stimulus amplitude (intensity) & duration
Why do neurons summate graded potentials?
A typical neuron receives many inputs which it integrates at the trigger zone to determine whether an action potential is produced.
What is temporal summation?
Summation of graded potentials from the same source at different times.
What is spatial summation?
Summation of graded potentials from two or more sources
What kind of potenial(s) occur at the trigger zone?
Both graded & action
What are the characteristics of action potentials?
-Long-distance signals
-Rapid depolarization followed by repolarization
-Don’t decrease in amplitude as they travel
-All or none
-Don’t summate
-Regenerated
What is a measure of intensity in action potentials?
Frequency
What is a neuromuscular junction?
Synapse between axon terminal of somatic motor neuron & motor end plate of skeletal muscle fiber
What occurs at the neuromuscular junction?
Neuronal action potential opens voltage-gated Ca2+ channels and allows exocytosis of Acetylcholine from axon terminal
Where can nicotinic acetylcholine receptors be found at the neuromuscular junction?
Skeletal muscle fiber membrane (sarcolemma)
What is the response from Ach release at the neuromuscular junction?
Always excitatory - tonic control = signal always “on” with no possibility of inhibition
What kind of receptor is nAChR?
Ionotropic: binding of ACh allows ion flow to depolarize the sarcolemma
What kind of potential is an end-plate potential (EPP)?
A graded potential - always excitatory
How does EPP potential produce muscle contraction?
EPP opens voltage-gated Na+ channels which always produces a sarcolemmal action potential that causes muscle contraction
What NT is secreted by the pre-ganglionic neuron in both the SNS & PSNS?
Acetylcholine
What is the type of receptor found on post-ganglionic neurons in both the SNS & PSNS?
Nicotinic AChR
What NT does the post-ganglionic neuron of the PSNS secrete?
Acetylcholine
What NT does the post-ganglionic neuron of the SNS secrete?
Norepinephrine
What is the type of receptor found on target cells of the SNS?
Adrenergic receptors
What is the type of receptor found on target cells of the PSNS?
Muscarinic
What is the relationship between cardiac output and MAP?
Incr. CO = Incr. MAP
What is the relationship between diameter of arterioles and MAP?
Decr. diameter = increase TRP = incr. MAP
How does NE change the diameter of arterioles?
Most systemic arterioles innervated by SNS neurons which release NE to incr. vasoconstriction through:
-alpha adrenergic receptors
-tonic control
What is the relationship between blood volume and MAP?
Incr. Blood Volume = Incr. MAP
What happens when Epi acts on alpha-adrenergic receptors?
Vasoconstriction
What are the responses to changes in blood volume in the cardiovascular system and kidneys?
Cardiovascular system = rapid
Kidneys = slow
What are baroreceptors?
Stretch-sensitive, respond to pressure
What occurs in the baroreceptor reflex when MAP is too high?
An incr. of baroreceptor firing toCVCC due to increase stretch of aorta:
-incr. PSNS to decr. HR
-decr. SNS to cause vasodilation
-overall decrease in CO & MAP
What is the intestinal phase?
Changes in secretion & motility stimulated by entry of chyme into duodenum
What does the presence of fats & proteins do during the intestinal phase?
fats & proteins stimulate CCK to stimulate pancreatic enzyme secretion &bile release by gallbladder
What is the role of acid in the intestinal phase?
Acid incr. secretin to stimulate bicarbonate secretion
What do carbohydrates do in the intestinal phase?
Carbohydrates stimulate incretins to stimulate insulin secretion
What happens to the activity of the stomach during the intestinal phase?
Gastric motility & acid secretion inhibited by ENS, secretin, CCK, and incretins
What does it mean that embryonic structures are bipotential?
Can develop into either female or male form
What determines if our embryonic structures are female vs. male?
-If no Y chromosome, then develop as female
-If Y chromosome, the presence of SRY gene causes development of testis
What do the testis secrete in embryonic structures?
-Anti-Mullerian hormone
-Testosterone (from DHT)
What happens in the HPG axis in both males and females?
Hypothalamus secretes GnRH which stimulates anterior pituitary to secrete the gonadotropins FSH & LH
What does LH (luteinizing hormone) do?
Sex steroid hormone secretion by gonads
What does FSH (follicle stimulating hormone) do?
Gametogenesis
What sex steroids do both sexes produce?
-Androgens: Testosterone & DHT
-Estrogens: Estradiol (E)
-Progestins: Progesterone (P)
What is aromatase?
Both ovaries and testes have aromatase which is an enzyme that converts T to E
What does LH do in the male gonads?
Activates Leydig cells to secrete testosterone
What does FSH do in the male gonads?
Activates Sertoli cells to secrete paracrines that increase spermatogenesis & secrete ABP to keep T from diffusing away
What is the negative feedback loop present in the male gonads?
Incr. Testosterone decreases GnRH, LH, and FSH
What does the menstrual cycle include?
- Ovarian cycle = changes in follicles of ovary
- Uterine cycle = changes in uterine lining
What is the menses phase of the uterine cycle?
If pregnancy is not achieved, shed endometrium which causes bleeding from uterus
What is the proliferative phase of the uterine cylce?
Endometrium thickens in preparation for pregnancy
What is the secretory phase of the uterine cycle?
Endometrial secretions promote implantation
What happens during the follicular phase of the ovarian cycle?
-Development of follicle cells
-Granulose cells proliferate and secrete estrogen
-Maturation of oocyte
What happens during the ovulation phase of the ovarian cycle?
Mature follicle bursts releasing oocyte
What happens during the luteal phase of the ovarian cycle?
-Ruptured follicle develops into corpus luteum
-Secretes progesterone & some estrogen to prepare for pregnancy
What does LH do in the female gonads?
LH tells thecal cells to secrete androgens that diffuses into granulosa cells, where aromatase converts into estrogen
What does FSH do in the female gonads?
FSh increases follicular development with help from the granulosa cells producing estrogen
What does the corpus leuteum do?
Secretes progesterone & some estrogen
What is the negative feedback loop in the female gonads?
An increase in E&P causes a decrease in GnRH, LH, and FSH
What does persistent high estrogen cause?
Switches to positive feedback and causes ovulation
What occurs during days 0-7 of the menstural cycle?
-Ovarian cycle: early follicular phase
-Uterine cycle: menses
-Hormones:
- FSH & LH increase
- Estrogen = low GnRH, LH, FSH
What occurs during days 7-14 of the menstural cycle?
-Ovarian cycle: Late follicular phase (follicular matures)
-Uterine cycle: Proliferative phase
-Hormones:
- Increased E changes to positive feedback to cause LH surge to trigger ovulation
What happens on day 14 of the menstrual cycle?
-Follicle ruptures and releases oocyte
-Thecal & granulosa cells start to become luteal cells
What happens days 14-21 of the menstural cycle?
-Ovarian Cycle: early luteal phase - corpus luteum develops
-Uterine cycle: secretory phase
-Hormones:
- Corpus luteum secretes P & E which decreases GnRH, LH, & FSH
What happens days 21-28 of the menstrual cycle if no pregnancy?
-Ovarian Cycle: late luteal phase - corpus luteum degenerates & ceases hormone production
-Uterine cycle: secretory phase
-Hormones:
- lack of P from corpus luteum = death of endometrium
- FSH & LH secretion resume
What happens if fertilization occurs?
-Fertilized egg implants in endometrium
-Placenta develops & secretes hCG to maintain corpus luteum
Why must the corpus luteum be maintained in the beginning of pregnancy?
Corpus luteum continues secretion of progesterone & estrogen - critical for maintaining pregnancy, but placenta eventually takes over progesterone production
What are oral contraceptives & what they do?
Synthetic estrogen & progesterone to decr. GnRH, LH, and FSH to prevent follicle maturation & ovulation
What is the function of the immune system?
-Protect body from pathogens
-Remove dead & damaged cells
-Remove “abnormal self” cells
What are the immune cells?
Leukocytes (white blood cells)
What are immunogens?
Anything that triggers immune response
What is an allergy?
Overeactive immune response
What is an autoimmune disease?
Incorrect immune response
What is immunodeficiency?
Lack of immune response
How do cells distinguish self vs. non-self cells?
Cell surface molecules
What are self-markers?
-Major histocompatibility complex on nucleated cells
-ABO & Rh blood types on RBCs
What are non-self markers?
Antigens are molecules that trigger immune response that bind to pattern recognition receptors on leukocytes
What antibodies do we have in our plasma for blood typing?
Have antibodies in plasma to any antigen that is not on our RBCs
What antigens does someone with type O blood have?
O antigens (recessive)
What happens if matching antigens & antibodies mix?
Blood cells clump
When considering blood transfusions, what do you need to know about the recepient?
What antibodies they have in plasma
When considering blood transfusions, what do you need to know about the donor?
Antigens on donor RBCs
What are the 3 lines of defense against pathogens?
- Barriers
- Innate immune response
- Adaptive Immune response
What is the barriers line of defense?
skin, mucous membranes
What is the innate immune response?
-non, specific & rapid
What is the adaptive immune response?
-B cells & T cells
-Slow
-Specificity: recognize & react to one antigen only
What is immunological memory?
For stronger & quicker response (acquired immunity) to subsequent exposures
How does the innate immune response remove dead & damaged cells?
Macrophages = primary scavenger
How does the innate immune response kill cells?
create pores in target cell membrane to kill it
How does the innate immune response use phagocytosis?
-Requires receptor binding
-may be assisted by antibodies
-target ingested and destroyed with lysosomal enzymes
-by phagocytes
What is inflammation?
Nonspecific reaction of immune system to foreign invader, part of innate immune response
How does inflammation occur?
-Mast cells secrete histamine which causes vasodilation to incr. blood flow causing redness & heat
-an incr. in capillary permeability allows proteins to enter the ISF causing edema & pain
-macrophages secrete cytokines which attract neutrophils
How does the innate immune response activate T cells?
-Antigen fragment is presented within self marker
-Performed by antigen-presenting cells
What do the the antigen-presenting cells (APC) do in the innate immune response?
-Dendritic cells = most important APC for initiating adaptive immune response
What cells are involved. inthe adaptive immune response?
-B cells, cytotoxic T cells, helper T cells
What does a correct match between antigen & receptor of the adaptive immune system do?
Activated cell to divide rapidly = clonal expansion
What are the cells that emerge from clonal expansion?
Effector cells (plasma cells) & memory cells
What is the primary response (first exposure to antigen) from the adaptive immune response?
-Initial response is slow
-Clonal expansion produces effector & memory cells
What is the secondary immune response (subsequent exposure) from the adaptive immune response?
-Due to memory cells, clonal expansion is more rapid allowing for a quicker, stronger response
What do B-cells do?
-Provides antibody-mediated immunity
-extracellular pathogens
What does activation of B cells require?
-binding to antigen
-cytokines from helper T cell
What do plasma cells do?
Secrete antibodies that attack to pathogen to tag them for phagocytosis
What do cytotoxic T cells do?
-Provides cell-mediated immunity
-Intracellular pathogens
-attack abnormal cells by creating membrane pores in target cell
What does activation of cytotoxic T cells require?
-Binding to matching antigen on APC
-Cytokines from helper T cell
What do Helper T cells do?
-Secrete cytokines
-Crucial in activating B cells and cytotoxic T cells
What does activation of helper T Cells require?
-Binding to matching antigen on APC
