Physiofuckology 2 Flashcards
what are the 2 ways to regulate a metabolic pathway and what are the features of each
Gene regulation - slower, but allows way more product to be formed
End product feedback inhibition - quicker
if first product is not used then it inhibits the first enzyme , slowing down the whole pathway
difference between magnetic resonance and diffusion weighted magnetic resonance imaging
magnetic resonance - used for diagnosing disease
diffusion weighted magnetic resonance - used for identifying connections
What do the CNS and PNS include
CNS - spinal cord, brain
PNS - spinal nerves, cranial nerves, ganglia
name the myelinating cells of the CNS/PNS and which is only found in the PNS
astrocyte oligodendrocyte microglia epyndemal cells only PNS - schwann cells
difference between white and gray matter
white - axons reside in white matter
gray - cell bodies reside in gray matter
what are the 4 brain divisions
cerebrum
diencephalon
cerebellum
brain stem
what are the divisions of the cerebrum
frontal lobe
temporal lobe
parietal lobe
occipital lobe
what is a sulci
the infoldings of the cerebrum that form valleys between gyri
what is a gyri
ridges of the unfolded cerebral cortex
in the cerebrum, which domain is responsible for what
frontal lobe - motor
parietal lobe - sensory
temporal lobe - auditory
occipital lobe - vision
what is each hemisphere of the brain dominant in
left - language and math skills
right - visual-spatial skills and creativity
what is homunculus
body is represented in an upside-down fashion in the sensory and motor cortices
what is located in the diencephalon and what are their functions
thalamus - major relay station for sensory information entering the cortex from the brain stem and spinal cord
hypothalamus - autonomic control centre - homeostasis
function of the brain stem
attaches spinal cord and cerebellum to the cerebrum
relay impulses between the cerebrum/diencephalon
division of the brain stem and their functions
midbrain - eye movement, reflexes
pons - major relay area between cerebrum and cerebellum
medulla oblongata - control centre for many involuntary functions
what protects the spinal cord
bone,meninges and CSF
name the protective tissue layers and their features
dura - strongest, usually in contact with bone
arachnoid - adhered closely to dura, web-like in appearance
pia - deepest layer, in direct contact with CNS tissue
what is CSF and what produces it and where is it located
cerebrospinal fluid - clear cell-free fluid
produced by the choroid plexus
located in the subarachnoid space
what is the BBB composed of, and what does it allow to pass through it
blood-brain barrier is composed of endothelial cells and astrocytes
allows O2, CO2, and lipid soluble molecules (hormones)
prevents free diffusion of molecules larger than 500 daltons
what divisions are in the motor system
visceral motor division
somatic motor division
difference between afferent and efferent
afferent - carries info into the CNS
efferent - carries info away from the CNS
difference between somatic and visceral
somatic - refers to the body wall and limbs
visceral - relates to internal organs
what division of the nervous system controls the visceral aspects of the body
ANS - autonomous nervous system
the visceral motor system can be divided into what?
sympathetic and parasympathetic nervous system
difference between a myotome and dermatome
myotome - provide sensory motor supply to an adjacent muscle mass
dermatome - cutaneous supply to an area of skin
steps of the reflex arc
receptor, sensory neuron, integration centre, motor neuron, effector
what does the spinal reflex show
somatic spinal reflex shows information on the integrity of the reflex arc and the level of excitability by the spinal cord
what is the resting membrane potential of a neuron
-70mV
what is the membrane potential of a neuron at step 1 of a membrane potential wave
-70mV - resting potential
what happens in step 2 of an action potential
membrane is passively depolarised
step 3 of action potential wave
voltage-gated Na+ channels open
Na+ depolarises the membrane
step 4 of action potential wave
positive feedback loop of more Na+ that enters causing more voltage-gated Na+ channels to open
rapid depolarisation
step 5 of action potential wave
peak depolarisation is reached
Na+ channels begin to close
K+ channels begin to open
repolarisation begins
step 6 of action potential wave
Na+ channels closed
Ka+ channels open
rapid repolarisation back to resting membrane potential
step 7 of action potential wave
repolarisation undershoots the resting value
final step of action potential wave
Na+ channels de-inactivate
K+ channels close
returned back to resting potential
what is the absolute refractory period
right after the spike of depolarisation, the membrane is not excitable because the Na+ channels are closed
why are only a few ions required to activate an action potential
because the lipids in the membrane are a capacitor which store electrical charge
what does Na+/K+ ATPase do
pumps out 3 Na+ ions for every 2 K+ ions pumped in
function of ouabain
blocks Na+/K+ ATPase
why when a neuron is at rest does it have a high energy state
because at rest the Na+ are not at equilibrium
resting membrane potential is largely determined by what
the selective permeability of the membrane to K+ ions, mainly
what are transposable elements
mobile DNA elements that translocate from one part of the genome to another
what are the 2 major classes of transposable elements
class I - retrotransposons class II - DNA transpososns
what is a titin filament
elastic filaments that run along the core of myosin and anchor it to the Z-line
what are the thin/thick filaments
thin - F-actin
thick - myosin
where is mitochondria mainly located and why
I band
close to the myosin and actin filaments
what is the structure of myosin
a dimer of 2 heads with intertwined tails
how does Ca2+ allow the myosin head to bind to the actin binding site
Ca2+ binds to the troponin which will cause the tropomyosin to move off the binding site
allows myosin head to bind to it
what is the connective tissue in smooth muscle called
endomysium
what releases the Ca2+ ions in a smooth muscle cell
calveole
function of Ca2+ activated calmodulin
activates myosin light chain kinase (MLCK)
how does phosphorylated MLCK allow myosin bind to actin
phosphorylated MLCK activates myosin ATPase
what do latch-bridges allow
allow for smooth muscle cell to maintain contraction even when Ca2+ is removed and myosin kinase is inactivated
what is a varicosity
varicosities are swollen regions found on an autonomic neuron which lines multiple smooth muscle cells
they contain vesicles containing neurotransmitters which are released when an action potential passes the varicosity
visceral muscle is connected by what and why
gap junctions
the muscle contracts as a single unit
what is the stress-relaxation response in visceral muscle
when a hollow organ is filled, the stretching induces a contraction in the visceral tissue
immediately followed by relaxation to prevent all contents from being expelled prematurely
what are multi-unit smooth muscle cells and where are they located
don’t contain gap junctions, electrical impulses are limited to the originally stimulated cell
large blood vessels
respiratory airways
eyes
function of intercalated disks
gap-junctions which allow the spread of excitation
what is end-diastolic volume
the amount of blood that fills the ventricles from venous return
approx. 110-120ml
what is the ejection fraction
the fraction of end-diastolic volume ejected from the ventricles
approx. 60%
what is end-systolic volume normally and for a strong contraction
amount of blood left in the ventricle after systole
normal - 40-50ml
stronger - 10-20ml
equation for cardiac output
CO = (EDV - ESV) x HR
what are the global controls for heart regulation
autonomous nervous system
Starling’s law
what are the local controls for heart regulation
nitric oxide
tissue pH
what causes an increase in K+ efflux and decreased Ca+ influx in the heart
parasympathetic neurones (ACh) signal to the muscarinic receptors on autorhythmic cells
what causes increased Na+ and increased Ca+ influx in the heart
sympathetic neurones (NAdr) signal to B1 receptors on autorhythmic cells
pressure difference / total peripheral resistance = ?
cardiac output
function of a sphincter
guard different sections and control movement through the digestive tract
name the 4 layers of the gastrointestinal tract
mucosa
sub mucosa
smooth muscle
serosa
what does the mucosa contain in the GI tract
transporting epithelial cells
connective tissue
nerve fibres
blood vessels
what does the submucosal contain
the submucosal plexis
features of smooth muscle in the gastrointestinal tract
important for lumen contraction
contains myenteric plexus
name the accessory organs of the digestive system
salivary glands
pancreas
liver
gall bladder
what are phasal contraction and what cells do they apply to in the digestive system
produce slow wave potentials, cycle of relax-contract
interstitial cells of cajal
what are tonic contractions and what cells do they apply to in the digestive system
long term contractions
sphincter cells
function of the submucosal plexus
contains sensory neurones that receives signals from the lumen and control secretion
function of the myenteric plexus
controls motitlity
function of smooth muscle in tracheobronchial tree
increase resistance
reduce dead space
function of cartilage in the tracheobronchial tree
increase dead space
reduce resistance
what causes the saline layer in the tracheobronchial tree
pseudostratified mucociliary epithelium
what is the Hz that the specialised cilia beat at
20Hz
how many alveoli are contained in 2 lungs
300 million
what surrounds the lung in the thoracic cavity
pleural fluid
how is a negative pressure between the visceral surface of the lung pleura and the parietal pleura of the thoracic cavity achieved
continual transfer of fluid into the lymphatic channels
what is pleural pressure
pressure in the intrapleural space
always slightly negative
what is alveolar pressure
pressure inside the alveoli
what is transpulmonary pressure
alveolar pressure - pleural pressure = transpulmonary pressure
what is the pleural pressure at the beginning of inspiration
-5cm
what is the pleural pressure at maximal inspiration
-7.5 cm of water
what is pneumothorax
when the lung collapses to its unstretched size
what does a lower compliance mean and what diseases cause this
lungs and thorax are harder to expand
pulmonary fibrosis
pulmonary oedama
how long does it take for blood to equilibrate with gases in a normal lung
0.2 seconds
how does increasing blood flow (perfusion, Q) effect O2 levels in the blood
has no effect
what can blood in lungs with oedema/fibrosis not do
reach full O2 saturation
full CO2 release
effects of increasing pulmonary arterial blood pressure
increases blood flow speed through capillaries from 0.8 to 0.25 seconds
opens collapsed vessels in the lung, increasing overall alveolar perfusion
what is the pulmonary/systemic capillary pressure
pulmonary capillary pressure - 7mmHg
systemic capillary pressure - 25mmHg
what are the 2 regulatory factors that determine O2/CO2 transfer between alveolus and tissue
rate of alveolar ventilation, V
blood flow, Q
not all alveoli are equally ventilated, where is V and Q higher and lower in the lungs
upper lung - V is higher, Q is lower
lower lung - V is lower, Q is higher
what is the ventilation perfusion ratio trying to achieve
balance between alveolar blood flow and alveolar ventilation
what is hypoxic vasoconstriction and why is it useful
when the pO2 drops in alveoli decreases, there is a decrease in blood flow to that alveoli
allows more blood to be directed towards alveoli with higher pO2
how does hypoxic vasoconstriction work
results of O2 sensitive K+ channels in the smooth muscle cell membranes in the arterioles
when low pO2, K+ channels close, causes the cell to depolarise and contract
causes arterioles to partially close
what does V/Q equal
0.8
how does hypoxic vasoconstriction maintain the ventilation perfusion ratio
V/Q < 0.8 in alveoli that has low pO2 but normal blood flow
after decreased blood flow the V/Q rises to about 0.8 again
matches the blood flow to gas exchange ability to minimise dead space
what is anatomical dead space
the volume of respiratory tract involved in conducting gas which isn’t transferring blood
what is physiological dead space
portion of tidal volume not participating in gaseous exchange with pulmonary capillary blood
what is Henry’s law
concentration of a gas in a liquid is determined by its partial pressure and its solubility coefficient
what is the equation to Henry’s law
concentration dissolved = PP of gas x solubility
when saturated how much O2 does 1 gram of haemoglobin carry
1.3mls
what % oxygen is transported in haemoglobin and plasma
haemoglobin - 98.5%
plasma 1.5%
at what partial pressure does the oxy-haemoglobin dissociation curve show that haemoglobin is fully saturated
80mmHg
what occurs during prolonged hypoxia (2-3hours)
more anaerobic glycolysis occurs
1,3-diphosphoglycerate and hence 2,3-biphosphoglycerate increases in blood and hence in RBC
what are the 4 factors that affect haemoglobin affinity for oxygen
H+ concentration (pH)
partial pressure of CO2
temperature
concentration of 2,3-diphosphoglycerate
what is the Haldane effect
central peptide of oxyhaemoglobin (lung) is a stronger acid than haemoglobin (tissue)
how is CO2 displaced in haemoglobin
H+ ions react at carbamino termini (-NH3) of Hb
when H+ ions react with the carbamino termini, what does the increased acidity cause
causes bicarbonate ions to form carbonic acid
carbonic acid dissociates into H2O and CO2 which is then released into the alveoli
function of C anhydrase
aids in the dissociation of carbonic acid into water and carbon dioxide
how is CO2 transported and the % each mode contains
bicarbonate ions - 70%
blood proteins - 24%
plasma - 6%
how does plasma pH regulate breathing
a drop in plasma pH indirectly causes an increase in respiration rate to drive off CO2
what does the respiratory control centre consist of and where is it located
several groups of neurons
located bilaterally in the medulla oblongata and pons
what does the dorsal respiratory group consist of and its function
dorsal medulla
mainly causes inspiration
constituents and function of the ventral respiratory group
ventrolateral medulla
modifies expiration and inspiration
location and function of the pneumotaxic centre
dorsally in the superior pons
mainly controls rate and depth of breathing
what happens when the dorsal respiratory group is separated from the lower and higher inputs
causes the neurons to spontaneously burst
leads to an intrinsic repetitive potential
location and function of the apneustic centre
located in the lower pons
prevents turn off of the ramp signal
what is the apneustic centre regulated by
vagal input - stretching of the lung
pneumotaxic centre
what does the pneumotaxic centre time
times the switch off point of the inspiratory ramp
what does a stronger signal from the pneumotaxic centre lead to
shorter inspiration - panting
what does the ventral respiratory area contribute to during heavy exercise and where does it send signals to
to both inspiration and expiration
sends signals to abdominal muscles
together what do the respiratory control centres have
basic rhythmic activity - DRC
regulatory activity - (pneumotaxic and apneustic centres)
to regulate lung activity, where from and to do signals reach and via what
several types of receptors in the lungs
peripheral chemoreceptors
transmit sensory signals through the glossophyrangeal nerves into the respiratory centres
in terms of respiratory regulation, what are cortical factors
voluntary respiratory control:
speech
swallowing
exercise
what stimulates the central chemoreceptors
the low pH in the cerebrospinal fluid
where is the chemo-sensitive area that detects H+ ions
in the medulla, lying directly under the pia
what is the Herring-Breuer reflex
stretch receptors on the walls of the lungs which send impulses to terminate inspiration
why is the Herring-Breuer reflex needed
prevents over expansion of the lung
co-ordinates the pneumotaxic and apneustic centres
when do peripheral chemoreceptors play a role
only when blood oxygen levels fall too low
pO2<70mmHg or 90% Hb saturation
how is dopamine released in response to low oxygen levels
carotid body chemoreceptors cells detect hypoxia
closes K+ channel leads to depolarisation
activated voltage-gated Ca2+ channels
results in exocytosis of dopamine
in terms of hypoxia, what is the effect of dopamine
increases the activity of the chemosensory afferent fibre
what is anaemic-hypoxia
low Hb content
CO poisoning - competes for Hb to form HbCO complexes
what is stagnant-hypoxia
poor circulation
shock
congestive heart failure
what is histotoxic-hypoxia
inhibition of oxidative processes by poisons
cyanide
how does cyanide kill
binds with cytochrome oxidase
prevents O2 from acting as a final electron acceptor
what does the cephalic reflex stimulate
ECL cells
parietal cells
what happens when acid acts on pepsinogen
pepsin is formed
what are zymogens
inactive enzymes secreted from the pancreas
name the zymogens secreted from the pancreas
trypsinogen chymotrypsinogen procarboxypeptidase procolipase prophospholipase
what activates trypsin and where is it located
enteropeptidase
brush border of the intestinal mucosa
what enzymes does trypsin activate
chymotrypsin
carboxypeptidase
colipase
phospholipase
function of hepatocytes and give an example of a bile acid and bile pigment
produce and secrete bile
bile acid - detergent
bile pigment - bilirubin
difference between GLUT2 and GLUT5
GLUT2 - hexose transporter
GLUT5 - fructose transporter
how is glucose transported from the small intestine into the blood
enters the intestinal mucosa from the lumen of the intestine with Na+ on SGLT
glucose then is transported in GLUT2
difference between endo and exopeptidase
endopeptidase - digests internal bonds in an amino acid chain
exopeptidase - digests from an amino acid chain from the terminals
how are amino acids absorbed into the small intestine
Na+ co-transport
how are di/tri-peptides absorbed into the small intestine
H+ cotransport
how are small peptides absorbed into the small intestine
endo/exocytosis
what is required for lipid emulsion and the product of it
bile
micelles
how is iron transported in and out of cells
in - DMT1
out - ferroportin
what are the ways Na+ can enter a cell
sodium channels
Cl- cotransport
proton pumps
where is primary lymphoid tissue found
bone marrow
thymus
where is secondary lymphoid tissue found
spleen
lymph nodes
features of innate immunity
immediate response
targets groups of pathogens
limited diversity of antigen receptors
no memory of pathogens
features of adaptive immunity
gradual response - over days
targets specific pathogens
highly diverse antigen receptors
produces immunological memory
what is the innate response to a virus
mucus
antigen presenting cells
phagocytes
cytokines
name the non-specific defences
skin mucous membrane temperature pH chemical mediators phagocytic inflammatory
name the non-specific chemical mediators
lysosomes
interferons
complement - lyses microbes
toll like receptors (TLRs)
what component of inflammation causes redness, swelling and heat
vasodilation
what is margination
attraction of blood monocytes and neutrophils into endothelial of venules
what is extravasation
emigration from the vessel between the endothelial cells into the tissue
what is chemotaxis
migration to the site of injury/invasion
what do monocytes differentiate into when they leave the bloodstream
macrphages
when is pathogen killing inititated
when the phagocytic vacuole fuses with the lysosome forming a phagolysosome
what does a phagolysosome release
oxygen radicals
chlorine products
nitric oxide pathway
what is NAHD oxidase and where is it located
a membrane bound enzyme complex
faces the inner space of phagosomes
what are used to destroy lipid membrane and bacterial DNA
superoxide hydrogen peroxide chlorine hypochlorite hydroxyl radical
what does superoxide dismutase convert super oxide into
hydrogen peroxide
what converts hydrogen peroxide into hypochlorite
myeloperoxidase
what are pattern recognition receptors
the innate immune system uses these to detect repeating patterns on the surface of the microorganism
what are mannose receptors
binds to mannose residues on the pathogen surface
what are glycan receptors
binds to polysaccharides on the surface of bacteria and yeast
what are scavenger receptors
recognise complex sugars on bacteria and yeast
what are toll-like receptors (TLR)
bind to lipopolysaccharides (LPS) on the cell wall of gram negative bacteria
what are complement receptors (CR)
recognise complement covered structures on yeast and bacteria
function of TLR
signals to immune cells the type of pathogen that has invaded
what releases IL-12
macrophages
what is IFNy (gamma) stimulated by
IL-12
what does IFNy lead to
further macrophage activation
leads to a feedback loop which amplifies the innate immune response
function of IL-1 and TNFalpha and what does this allow
induce endothelial cells to express adhesion molecules
allows neutrophils and monocytes to leave the bloodstream
what is IL-8
a potent neutrophil chemoattractant
activates macrophages
what interleukins increase endothelium permeability
TNFalpha
platelet activating factor (PAF)
PG
what is a complement
a group of plasma and cell membrane proteins that lead to the formation of a membrane attack complex and inflammation
bitches cant take em
what triggers the acute phase
if the reason for the inflammation is not eliminated, cytokines in the blood rise
causes a systemic acute phase
what does IL-1 cause in the brain
fever
sleepiness
anorexia
what does IL-6 do in the liver
stimulates hepatocytes to release many acute phase proteins
these rise by 100-1000x
what is opsonisation and when does it occur
C-reactive proteins binds phosphocholine on pathogenic organisms and damaged cells to facilitate uptake
occurs during the acute phase
function of phospholipase C
hydrolyses negatively charged bacterial membranes
what are the cells of the adaptive immune response
B cells
CD4+T cells
CD8+T cells
what cell is active in the humuoral immune response
B cell
what cells are active during the cellular immune response
CD4+ T cells
CD8+ T cells
where are T-lymphocytes derived from
thymus
where are B lymphocytes derived from
bursa of fabricus in bone marrow
what do B-lymphocytes produce
immunoglobulins - Ab antibodies
what are antibodies
opsonins that binds proteins, sugars and sometimes lipids
in terms of Daltons how heavy are the heavy and light chains of antibodies
heavy chain - 50-75kDa
light chain - around 25kDa
what is the hinge region of an antibody composed of
prolines in an alpha-helical structure
what does an antibody bind to
a specific part of the antigen called an epitope
how big is the epitope
8-22 amino acids
what is avidity
binding of a whole antibody ( 2 or more epitope bindings)
difference between a monoclonal and polyclonal antibody
monoclonal - produced by 1 B-cell and recognises only one epitope
polyclonal - produced by multiple B-cells and recognises multiple
what are the 5 classes of antibodies
IgM IgG IgA IgE IgD
what is the most abundant antibody
IgG
70%
what are the first 3 functions of antibodies
1 - activates B-lymphocytes
2 - acts as opsonins to tag antigens for phagocytosis
3 - causes antigen clumping and neutralises pathogenic toxins
what are function 4-6 of antibodies
4 - activate antibody-dependant cellular activity
5 - activate complement
6 - trigger mast cell degranulation
specific function of CD4+T cells
immunity against intracellular bacteria and parasites
provides help to CD8+T cells
promotes humoural immune response
features of CD8+T cells
when activated they become cytotoxic
kill virally infected cells
kill tumour cells
where do all blood-borne immune cells originate from
hematopoietic stem cells (HSC)
what is hematopoiesis
formation of erythrocytes (RBC)
when and where does hematopoiesis occur
3rd to 7th months of gestation
from liver to spleen
difference between live attenuated vaccines and inactivated vaccines
live attenuated - weakened version of the virus
inactivated - killed virus
what is a recombinant vaccine
targeted towards a specific sub-unit of the virus
what is a toxoid vaccines
toxin released by the virus
what are the forces during glomerular filtration
capillary blood pressure - 55mmHg
osmotic pressure - 30mmHg
fluid pressure - 15mmHg
what is GFR
filtration efficiency
what is filtration coefficeint
surface area of glomerular capillaries
permeability of endothelial cells
what happens in terms of arterioles in the kidney if there is high blood pressure
afferent arterioles constrict
efferent arterioles dilate
what is the auto regulatory range for renal blood flow pressure
80mmHg - 180mmHg
out of the substances that pass through the kidneys, which one isn’t reabsorbed
creatinine
