bio deck 2 Flashcards
what happens at the sodium-potassium exchange pump?
the sodium-potassium exchange pump maintains the cell’s resting potential by ejecting three sodium ions for every two potassium ions it brings in from the ISF
(3 Na+ out; 2 K+ in)
what effect would a chemical that blocks the voltage-gated sodium channels in the plasma membrane of a neutron have on its ability to depolarise?
if the voltage-gated sodium channels couldn’t open, sodium ions could not flood into the neutron and it would not be able to depolarise
describe four features of a polarised neuron
resting membrane potential
-70 volts
more K+ inside
more Na+ outside
which branch of the ANS has short pre-ganglionic fibres and long post-ganglionic fibres?
sympathetic
in which branch of the ANS do pre-ganglionic fibres release acetylcholine?
both
in which branch of the ANS do the post-ganglionic fibres release noradrenaline?
sympathetic
in which branch of the ANS do the post-ganglionic fibres release acetylcholine?
parasympathetic
may increase or decrease activity of effect (slows heart rate; increases motility)
what is special about cranial nerve x?
it’s the only non local cranial nerve
what is atmospheric pressure at sea level?
760mm Hg
where is the atrioventricular node located?
in the floor of the right atrium, near the septum
what is the significance of protein in the urine?
consistent presence suggests glomerular of tubular damage
transient proteinuria quite common
can indicate a UTI
what is the chemical symbol for carbonic acid?
H2CO3
what is the left AV valve also know as?
bicuspid valve or mitral valve
which layer of the blood vessel contracts to cause vasoconstriction?
smooth muscle of the tunica media
what is isovolumetric contraction?
all valves are closed, ventricles contractin
what is thrombin’s action in the clotting cascade?
converts fibrinogen into fibrin
what is CO2?
carbon dioxide is a byproduct of aerobic metabolism (cellular metabolism)
what is pulse pressure?
the difference between systolic BP and diastolic BP
what are the cells of the blood and where are they formed?
RBCs, WBCs and platelets
all formed in the bone marrow
what is the most common circulating WBC? what is its purpose?
neutrophils
phagocytosis
what are ketones, and what is indicated by their presence in the urine?
breakdown products of fat metabolism
they indicate the body has run out of glucose
ketones can be very high in diabetes; indicating an insulin deficiency
what NT causes vasoconstriction? what is the receptor for this NT?
noradrenaline
adrenergic receptors
what is MAP going to be in a person with 120/80 BP?
MAP = diastolic BP + 1/3 pulse pressure
80 is diastole
PP is 120 - 80 = 40
one third of 40 is 13.3
therefore MAP = 93.3 (80 + 13.3)
what breaks down the fibrin in a clot?
plasmin
what is fibrinolysis?
the slow process of dissolving a clot once healing is complete
where is angiotensinogen produced?
the liver
what does RAAS stand for?
renin-angiotensin-aldosterone system
what are the two types of cardiac muscle cell and what do they do?
conducting system cells: control and coordinate the heartbeat
contractile cells: produce contraction that propel blood
what two things does oxytocin stimulate during childbirth?
uterine contractions
production of prostaglandins in endometrium which stimulate further uterine contractions
what hormones are secreted by the testes?
androgens, including testosterone
inhibin
what do width and height equal on an ECG?
height equals voltage
width equals time
what effect would an increase in venous return have on stroke volume?
increased venous return = more stretch in heart muscle = greater force of contraction = higher stroke volume
what does isovolumetric mean?
all valves are closed.
same volume.
like squeezing a bottle with the lid on - pressure increases, but volume remains the same
what part of the lungs is regulated by the autonomic nervous system?
the bronchioles
what effect would an increase in sympathetic stimulation of the heart have on end-systolic volume?
increased heart rate and increased force of contraction leads to higher stroke volume = lower end-systolic volume
which cells produce antibodies?
plasma cells
define end-diastolic volume (EDV) and end-systolic volume (EDV)
EDV - amount of blood in left in the ventricle at the end of relaxation
ESV - amount of blood left in the ventricle at the end of contraction
list the phases of the cardiac cycle
atrial systole
atrial diastole
ventricular systole
ventricular diastole
describe the blood supply to the brain
two internal carotid arteries
two vertebral arteries - join to form basilar artery
all join to form the arterial circle of Willis
what is stroke volume?
the amount of blood that leaves the heart with each beat
ml/beat
which blood vessels supply the heart with oxygenated blood?
coronary arteries
cardiac veins
what are the three functions of platelets?
release important clotting chemicals
temporarily patch damaged vessel walls
reduce size of a break in vessel wall
which hormone regulates the secretion of potassium in the nephron?
aldosterone
ADH
- where?
- what?
anti-diuretic hormone
made in the hypothalamus, secreted by the posterior pituitary gland
causes kidney to retain water; less urination leads to increased blood volume, therefore increased BP
describe the pericardium
pericardial sac - visceral and parietal layers with pericardial cavity containing pericardial fluid in between
serous membrane!
dopamine - physiology?
-pathophysiology?
neurotransmitter
dopaminergic receptors
can be excitatory or inhibitory
physiology: motor control emotion and reward decreased prolactin vomiting
pathology:
schizophrenia
parkinsons
addiction
acetylcholine
physiology?
pathophysiology?
neurotransmitter
physiology: cognition learning and memory consciousness motor control
pathophysiology:
alzheimers
glutamate
physiology?
pathophysiology?
amines
main NT in brain
NMDA receptor
physiology:
learning and memory
pathophysiology
epilepsy
chronic pain
drug dependence
noradrenaline-
physiology?
pathophysiology?
neurotransmitter
physiology
arousal and mood
blood pressure
pathophysiology
bipolar disorder
depression
5HT:
physiology?
pathophysiology?
there are lots of 5HT receptors
physiology - digestion sleep/wake mood appetite vomiting
pathophysiology
depression
mania
eating disorders
what are the steps of carcinogenesis?
initiation
proliferation
progression
pharmacodynamics of NSAIDs
competitive inhibition of cox-1 and cox-2 inhibitors
inhibits prostoglandin synthesis
what are the monoamine NTs?
noradrenaline adrenaline dopamine 5HT histamine (excitatory)
describe the nerve supply of the kidneys
sympathetic fibres regulate renal blood flow according to the body’s requirements
what is RV?
residual volume = amount of air left in passageways and lungs after maximal exhalation
about 1200ml men//1100ml women
what hormones do the ovaries secrete?
oestrogen
progesterone
inhibin
what is normal tidal volume at rest?
200-500ml
in kidney autoregulation, what mechanisms are used to increase glomerular blood pressure?
dilation of afferent arterioles
constriction of efferent arterioles
contraction of mesangial cells
what is the process that forms new bone matrix known as?
osteogenesis
describe a muscle
fascicles (bundles of muscle fibres) surrounded by the epimysium
what is the connective tissue layer that surrounds each fascicle?
the perimysium
what is VC?
vital capacity - the amount of air you can move through the lungs
IRV+TV+ERV
about 4.8L men // 3.3L women
what is another name for a diarthrosis joint?
synovial joint
what are the characteristics of cardiac muscle cells?
small
branched
single nucleus
intercalated discs
what is the layer that surrounds a bone called?
periosteum (but not within joint cavities)
define the respiratory defence system
a series of filtration mechanisms the prevent airway contamination by debris and pathogens
includes mucociliary escalator
what physical changes affect the total volume of the lungs?
movement of the diaphragm and ribs
define nerve
bundle of nerve fibres
why is the lining of the nasopharynx different from that of the oropharynx and the laryngopharynx?
nasopharynx and nasal cavity - psuedostratified ciliated columnar epithelium - this area only receives air through the nose.
oropharynx and laryngopharynx need more protection as they also have contact with food, so have stratified squamous epithelium
identify the neuroglia of the CNS
ependymal cells
astrocytes
oligodendrocytes
microglia
between which two layers of the meninges is the CSF?
CSF is in the subarachnoid space between the arachnoid mater and the pia mater
which glial cell protects the CNS from chemical and hormones circulating in the blood?
astrocytes maintain the blood brain barrier
what three things protect the brain from mechanical forces?
cranium bones, cranial meninges, CSF
which neuroglia in the CNS myelinated and stabilise axons?
oligodendrocytes.
each one will myelinated several axons; each axon is myelinated by several oligodendrocytes
describe the neurilemma
the outer surface of a Schwann cell when it covers an axon is called the neurilemma
what is the main neurotransmitter?
glutamate
what is inflammation?
a localised tissue response to injury that stimulates immune response and enables healing
what kind of immune defence is inflammation?
second line, non-specific defence
what is the purpose of inflammation?
destroys/neutralises the injurious agent (limits the extent of injury)
stimulates immune response
cleans up dead tissue and debris
enables healing
what are the stimuli for inflammation?
infections trauma physical agents (radiation or temps) chemical agents ischemia/tissue necrosis foreign bodies immune reactions genetic defects
describe the vascular phase of inflammation
- vasoconstriction
- vasodilation
- increased blood flow
- redness and warmth - increased vascular permeability - ‘leaky capillaries’ -
- plasma -> interstitial fluid -> oedema
describe the cellular phase of inflammation
leukocytes are recruited from the blood
they migrate to the site of injury via chemotaxis
leukocytes are activated to perform phagocytosis
what’s the difference between acute and chronic inflammation?
chronic inflammation
- persistent
- two weeks +
- associated with tissue destruction
- macrophages and lymphocytes main WBCs instead of neutrophils
what are the systemic effects of inflammation?
fever (due to increased prostoglandins) malaise anorexia degradation of skeletal muscle proteins increased hepatic protein synthesis leukocytosis (increased WBCs)
what are the six links in the chain of infection?
infectious agent reservoir portal of exit means of transmission portal of entry susceptible host
what are the modes of transmission?
contact - direct
- indirect (fomites)
- droplets
via vehicle - non living agents such as air, water or food
via vectors (living agents)
- mechanical vectors such as flies
- biological vectors such as mosquitos
what is first line defence?
- non specific
- prevents entry of antigens into cells
eg skin tears, mucus, saliva, sweat stomach acid beneficial bacteria urine flow flushes bacteria from bladder
can also include neutrophils
what is the fluid that exits capillaries during inflammation due to leaky capillaries called?
exudate (protein rich)
what are mediators of inflammation?
chemicals released from cells (eg histamine, prostoglandin, thromboxanes)
and/or chemicals in the bloodstream (eg in the complement cascade)
what are the phases of inflammation?
vascular phase
cellular phase
vascular phase - changes in cascular calibre and flow
cellular phase - emigration of white blood cells
how do antibodies cause elimination of antigens?
- activation of the complement cascade
- attraction of phagocytes
- stimulation of inflammation
- prevention of viral/bacterial adhesion
- precipitation and agglutination
- neutralisation
- opsenisation
what are the ‘pathogenic properties’ of a microorganism?
AITEA adherence invasiveness toxins evasiveness antibiotic resistance
list the chemical agents of disinfection
soaps/ detergents
acids/alkalis
alcohols
chlorine (bleach)
what’s the difference betweeen sterilisation, disinfection and cleaning?
sterilsation is the complete destruction of all living material, including spores (steam under pressure, chemical, radiation)
disinfection destroys most agents, reducing them to a safe level (chemical, heat)
cleaning removes surface material (only clean things can be disinfected)
what are the types of adaptive or specific immunity?
active - make your own antibody
passive - ready made antibodies given
naturally acquired - come into contact in the natural course of life
artificially acquired - needs outside intervention
*naturally acquired passive: ie through breast milk or the placenta
types of vaccines
live attenuated
- weakened live microorganism
- not for the immunosuppressed
- great immunity
- MMR, varicella
inactivated
- less immunity
- more adverse reactions
- polio, hep A, rabies
subunit (just the antigen)
- safe
- hep B, HPV
toxoid
what is an antibody?
a protein secreted by plasma cells,
it binds with a specific antigen and promotes its removal or destuction
also known as an immunoglobulin
give an example of mechanical vector transmission.
contrast with biological vector transmission.
mechanical - fly lands on poo, then on food - passively spreading disease
biological vector involves a bite from a mozzie, tick etc
at any moment, where are most of the body’s lymphocytes to be found?
in connective tissue and the organs of the lymphatic system ( and a small percentage are circulating in the blood)
what are the three types of lymphocytes?
t cells, b cells and NK cells
explain the difference between specific and non-specific immunity
non-specific defences are innate (you’re born with them) and they don’t distinguish between potential threats - they respond the same way every time
specific defences have to be activated, and provide an adaptive defence against that particular antigen/pathogen
what are the lymphoid organs and tissues?
red bone marrow, thymus, spleen, tonsils, appendix and MALT tissue
where is MALT tissue found?
the digestive, urinary, respiratory and reproductive tracts
what does MALT stand for?
mucosa-associated lymphoid tissue
in what ways do lymphatic capillaries differ from blood capillaries?
they originate as pockets rather than forming continuous tubes
they have larger diameters
the have thinner walls
they typically have a flattened or irregular outline in sectional view
which areas of the body lack lymphatic capillaries?
those without a blood supply, such as the cornea of the eye, as well as the red bone marrow and the CNS
what are the four main types of t cells?
cytotoxic t cells, helper t cells, suppressor t cells and memory t cells
what can b cells differentiate into when stimulated?
plasma cells, which produce and secrete antibodies
what are the main cells involved in antibody-mediated immunity?
b cells
what is antibody-mediated immunity also known as?
humoral immunity (humoral meaning liquid, as antibodies are found in body fluids)
what is the function of overlapping endothelial cells in lymphatic capillaries?
they act as one way valves that permit the entry of fluids, solutes, and pathogens but prevent their return to the intercellular spaces
compare lymphatic capillaries in the small intestine with those found elsewhere
lymphatic capillaries in the small intestine are called lacteals and transport lipids
which cells are responsible for cell-mediated immunity?
t cells, particularly cytotoxic t cells
what type of immune response are NK cells involved in?
non-specific immunity. they continually monitor peripheral tissues for foreign cells, virus-infected cells and cancer cells - known as immune surveillance
what are the tonsils and where are they located?
large lymphoid nodules in the walls of the pharynx
name the five tonsils
pharyngeal (aka adenoid)( in the nasopharynx)
left and right palatine tonsils (at the border of the oral cavity and the pharynx)
lingual tonsils (pair at the base of the tongue)
what are the clusters of lymphoid nodules deep to the epithelial lining of the intestine known as?
Peyer’s patches
where is the thymus located?
in the mediastinum, generally just posterior to the sternum
what is the largest lymphoid organ?
the spleen
what is the role of the spleen in the body?
essentially, it performs the same functions for blood as the lymph nodes perform for lymph:
- removing abnormal blood cells and other components via phagocytosis
- storing iron recycled from red blood cells
- initiating immune responses by B cells and T cells in response to antigens in circulating blood
what are the largest lymph nodes also known as, and where are they found?
also known as lymph glands, found where the peripheral lymphatics from neck and limb connect with the trunk - base of neck, groin, armpits
what do lymph nodes do?
function like a kitchen water filter, straining and purifying the lymph before it returns to venous circulation
they remove at least 99% of antigens in the lymph as it flows through, and stimulate an immune response as needed
what are the body’s innate defences?
physical barriers (skin, mucous membranes) phagocytes immune surveillance (by NK cells) interferons the complement cascade inflammation fever
how does the integumentary system protect the body?
provides a physical barrier that is a first line of defence in preventing pathogens and toxins from entering the body
- secretions flush the surface
- hair and nails protects against physical abrasions
- multiple layers of the epithelium create an interlocking barrier
what are the body’s first-line defences?
first-line defences are non-specific, and stop an antigen from getting into the body
they can be physical, chemical or biological
what are the body’s second-line defences?
second-line defences are non-specific, and limit the spread of an antigen once it is in the tissues
- phagocytes and NK cells
- inflammations
- fever
- antimicrobial compound chemicals such as interferon and the complement system of plasma proteins
what are the different types of phagocytes?
neutrophils, eiosinophils and macrophages
what is chemotaxis?
phagocyte movement in response to chemical stimuli
which cells are responsible for recognizing and destroying the body’s own abnormal cells?
NK cells
how do NK cells detect cancer cells?
plasma membranes of cancer cells generally contain abnormal proteins called tumor-specific antigens
define interferons
small proteins that are released by activated lymphocytes, macrophages and cells infected by viruses
they trigger the production of antiviral proteins that interfere with viral replication within tissue cells
what is a cytokine?
a chemical released by a cell to coordinate local activities, for example interferons.
most cytokines are used only for cell-to-cell communications within a tissue, but those released by phagocytes and lymphocytes can also act as hormones, affecting cells and tissues throughout the body
what is the effect of histamine release?
histamine release by mast cells and basophils increases local inflammation, accelerating blood flow to the region
what is the complement system?
special proteins in plasma which complement the actions of antibodies.
they interact with each other in a cascade, similar to the blood clotting system
what are the cardinal signs of inflammation?
redness, swelling, warmth, pain, loss of function
what is fever?
a generalised response to tissue damage and infection
what role does fever play in the body’s immune response?
high body temps may inhibit some viruses and bacteria
increase in body temperature leads to increase in body’s metabolic rate, so that tissue defence systems are mobilised more quickly and repair process speeds up
what effect do pyrogens have in the body?
they reset the temperature thermostat in the hypothalamus, increasing the body temperature
which cells coordinate specific (adaptive immunity)?
B cells, T cells
what is the difference between cell-mediated and humoral immunity?
cell-mediated immunity - t cells (generally) defend against abnormal cells and pathogens inside cells
humoral immunity - b cells produce antibodies which defends against antigens and pathogens in bodily fluids
modes of transmission: what is the difference between vetical direct contact and horizontal direct contact?
vertical - mother (or father) to child: in utero, during childbirth or postnatally, including via breastmilk
horizontal is peer to peer, usually via contact with excretions/body fluids
what is the name of an inanimate object capable of transmitting organisms?
a fomite
what are the five classes of antibodies?
IgA: found primarily in glandular secretions: mucus, tears,
saliva, semen; but also in in blood
-Attack pathogens before they gain access to internal
tissues
IgD: B cell surfaces, bind with antigens in ECF and plays a
role in sensitising B cells
-IgD is membrane-bound, is a marker of maturity in b cells, and the exact action is not perfectly understood
IgE: active in allergies, protection from parasites
- chain end binds to active sites on mast cells and basophils, with fab area ready to bind to antigen
- Once bound to an antigen, mast cell releases histamine and accelerates inflammation
IgG: ‘memory’ antibody (80% of antibodies)
- responsible for resistance against many viruses,
bacteria and bacterial toxins
- Smaller, can cross the placenta
IgM: first one made after antigen encountered
- IgM population declines as IgG population increases
- Anti-A and anti-B antibodies responsible for
agglutination of incompatible blood types are IgM
which cells produce antibodies?
plasma cells
