Bits and Pieces Flashcards
What is the difference between a generalised and a localised system, give an example of each.
Generalised - distrib through body i.e. cardiovascular
Localised - in one area only i.e. reproductive
What is the difference between the carotid artery and the jugular vein
Carotid: heart to head
Jugular: head to heat
Give examples of amorphous extracell. and fibrous extracell. material
Amorphous: jelly like - blood, lymph or solid - cartilage and bone
Fibrous: collagen, reticular, elastic
What can be found on the apical, lateral and basal surfaces of epith. cells
apical: cilia, microvilli, stereocilia
lateral: interdigitation or junctional complexes
basal: striations, basement membrane, hemidesmosomes
What are the embryonic origin layers for skin, gut and cavities?
Skin: ectoderm
Gut: endoderm
Cavities: mesoderm
What is the difference between flexion, extension and hyperextension in terms of body movement (feet/hands)
flexion; folded up like when asleep
extension: straight line from ante brachium/crus
hyperextension: dorsal flexion/plantigrade stance
The pectoral limb: scchurc’mp
probs of no help but to me :)
scapula, clavicle, coracoid, humerus, ulna, radius, carpal bones, metacarpals, phalanges
The pelvic limp: iiapfpft’mp
probs of no help but to me :)
ilium, ischium, acetabular bone, pubis, femur, patella, fibula, tibia, tarsal bones, metatarsal, phalanges
What solutes are high intracellularly?
K+, Mg2+, phosphates, proteins,
maintained by active transport
What solutes are high extracellularly?
Na+, Cl-, Ca2+, HCO3-
Where are discontinuous capillaries found?
bone marrow, liver and spleen - permeable to large molecules
What three things make up ficks law
SA, conc. difference, thickness of diffusion pathway
List the 4 functions of the lymphatic system
1) control blood vol and extract vol (return oncotic protein to blood)
2) absorption of fat
3) immune surveillance
4) metabolism and turnover of extracell matrix constit
Where is there no lymphatic tissue?
CNS, eye and bone
What is lymphodema? How does it occur?
obstruct of lymph drainage = build up of lymph fluid can be from lack of sufficient lymph vessels, radiotherapy destroyed or surgery
Where do platelets come from?
fragments of megakaryocytes from one marrow
What is a Heamopoietic stem cell and how is it controlled?
multipotent precursor of amyloid, lymphoid or erythroid cells.
regulated by stream fibroblast, osteoblast, endoth, cell and extracell matrix - receptor binding needed
What are the three roles of EPO
shortens cell cycle
increases rate of maturation
increases rate of release from bone marrow
Why and where is EPO released from?
from kidney
why: fall of RBC’s, tissue hypoxia
How do platelets form? What stimulates this?
megakaryocytes increase DNA and cytoplasmic volume –> platelets bud off
stimulated by thrombopoietin (TPO)
Where are monocytes stored
they are not stored - released into blood after production
List the four things the immune system requires to be functional
1) inactivity to itself
2) specificity - be able to recognise non-self
3) recognition of microbes and proteins - antigens, PAMPS
4) be able to destroy foreign/abnormal material - phagocytosis
Where are B cells derived from?
bone marrow, peyers patches in ruminants and bursa of Fabricius in birds
How does mast cell action vary between GI tract, Airways and Blood vessels?
GI tract: increase fluid secretion and peristalsis
Airways: decrease diameter, increase mucus
Blood vessels: increase blood flow, increase permeability = higher lymph flow
What are some common autacoids?
- histamine
- bradykinin and substance P –> vasodilation, itch and pain
- cytokines
- Eicosanoids - PGs, thromboxanes and leukotrienes
How can leukocytes migrate into tissue to cause inflam?
toxins and proinflam cytokines activate endothelium = expression of cell adhesion molecules = leukocytes stick and slowed down –> emigration into tissue where they release enzymes and ROS = clear dead tissue and microbes (init good)
What are the differences between serous, catarrhal, fibrinous and suppurative inflam?
- serous - minimal increase in permeabil. forms serous exudate
- catarrhal - exudate formed on mucosal surface. serous fluid with mucus, inflam cells and cell debris
- fibrinous - greater permeabil fibrinogen out = fibrin –> yellow gel like bread and butter
- suppurative = pus, thick and creamy with neutrophils
What is a phlegmon?
diffuse suppurative inflammation in loos connective tissue (cellulitis)
What is an empyema?
assume of pus in body cavity
What cell population change happens in chronic vs acute inflam?
neutrophils –> macroph. (3 days) to lymphocytes and plasma cells (7-10 days)
What does granulation tissue look like - is it the same as granulomatous inflammation? When does it occur?
Not the same as granulomatous inflammation = macrophage rich
It is pink, soft, moist and bumpy, well vascularised (angiogenesis occurs) but no nerves = no pain. It occurs in the repair of inflammation - fibroblasts eventually migrate through = fibrin scaffold and collagen.
What is the difference between primary and secondary intention healing?
primary - if directly opposing wound edges
secondary - extensive tissue loss need greater volume of granulation tissue, more extensive scar contraction - may restrict movement
What is proud flesh?
excessive proliferation of granulation tissue, tumour like masses
What is keloid?
unsightly proliferation of scar tissue - very dense collage
How can a low energy balance cause hydraulic degeneration?
Na+/K+ ATPase is the main regulator for electrolyte balance that then drives water uptake/exit. With low energy this ATPase doesn’t function
What happens to fatty acids that enter the liver?
- oxidised in mitochondria
- used for cholesterol and phospholipids
- oxidised to ketone bodies
- esterified to make VLDL to go into circulation
How is VLDL made and what problem occurs if a step is compromised?
fatty acid –> esterified to triacylglyceride –> bound with apoprotein —> packed into VLDL –> circulation
if this is compromised (apoprotein synthesis or packaging into VLDL) = fatty change
What does a corticosteroid do?
induces transcription of glycogen synthetase = excessive storage of glycogen = steroid hepatopathy
What are hyaline droplets and what do they stain as?
they are accumulations of proteins within cytoplasm. Eosinophilic staining.
What do glyoproteinoses, sphingolipidoses, glycogenoses and ceroid-lipofuscinoses have in common?
All inherited lysosomal storage disorders where substrate cannot be broken down (enzyme disfunction/absence or absence of activator protein) - accumulate in lysosome
Can lysosomal storage disorders be acquired?
Yes - exogenous toxins such as swainsonin/alkaloid inhibiting lysosomal alpha mannosidase
How can you identify amyloidosis?
It is an amorphous, eosinophilic extracell. material. Stains red with Congo red stain.
What are the two main forms of necrosis?
a) oncotic = death by swelling, membrane breakdown = leak. More common and pathological, involves immune response.
b) apoptosis = cell suicide, death by shrinkage - chromatin, fragmentation –> phagocytosis.
What is the pathogenesis of Apoptosis?
Suicide - uses cells own caspase enzymes –> cleaves cytoskeletal proteins, activates endonuclease, cleaves nuclear proteins. Flipping of phospholipid membrane = abnormal –> phagocytosis
What is the pathogenesis of oncotic necrosis?
cell membrane injury = influx of calcium into cell = intracellular messenger and enzyme activator.
- phospholipases active = membrane destruction
- Atlases accelerate ATP depletion
- proteases - destruct membrane and cytoskeleton
- endonucleases - degrade nuclear chromatin
Cell death = release of cellular contents - stimulate immune response. Degradation by own lysosomal enzymes (autolysis) or recruited leukocytes (heterolysis)
List the three different appearances of the nucleus
pyknosis: shrunken, dark staining
karyorrhexis: rupture of nuclear envelope
karyolysis: fading nucleus (RNA/DNAases)
How can you grossly see oncotic necrosis?
Sharply demarcated from viable tissue as active inflamm reaction. red border (hyper perfusion), internal white border (leukocytes with lysosomal enzymes)
What are the two types of gangrenous necrosis, what do both stem from?
Both from coag necrosis.
1) dry - mummified by dehydration
2) wet/gas - necrosis then colonisation by bacteria –> liquefaction and putrefaction
What are differences between liquefactive and caseous necrosis?
liquefactive - from rapid degradation of cells and accumulation of neutrophils = pus
Caseous - dry debris +/- mineralisation often with rim of inflammation or fibrous tissue capsule
What are some causes of fat necrosis?
- lipolytic enzymes from necrotic exocrine pancreas
- trauma
- ROS damage as deficient in Vit. E and selenium
- hypoxia
What is dystrophic mineralisation?
Accumulation of calcium salts in tissues with oncotic necrosis = gritty, hard, chalky foci
intracel - accum of Ca2+ in mitochondria of dead cells
extracell = ca2+ to membrane phosphates of disintegrating cells = mycrocrystal formation
Give an example of an environmental signal
light = change in rhodopsin (photoreceptive protein) -> activates transducin -> cGMP lowered
What is the function of a tropic hormone?
to regulate hormone production of another cell
Where is the pituitary gland located and how is it divided?
it is in the sella truck, connected to the hypothalamus by the sella turcica. Divided into anterior and posterior pituitary.
which pituitary portion receives portal venous inflow? What does this breach?
Only the anterior pituitary - breaches BBB
Where does the hypophyseal artery enter?
In the primary capillary plexus - in lower hypothalamus, takes up inhabit or releasing hormones –> portal system to secondary capillary plexus
What are the factors influencing release of Growth Hormone?
Growth hormone releasing hormone
Somatostatin (inhibits)
Ghrelin (peptide hormone from stomach, stimulates)
stress, exercise, nutrition, sleep, GH itself
What is ACTH and what does it do once in the bloodstream?
Adrenocorticotrophic hormone
To adrenal cortex = glucocorticoid release (cortisol, adrenal androgens)
Influenced by stress, circadian rhythms, feedback
What is the half life of a peptide hormone like?
short as unbound to plasma protein
What to thyroid hormones and catecholamines have in common? How are they different?
Both amino derived
Thyroid - lipid soluble = intracel. target
Catecholamins - hydrophilic - alpha and beta surface receptors
What inhibits prolactin release?
Dopamine from hypothalamus - if stalk cut = no dopamine, so prolactin levels rise.
What does low affinity mean in terms of the number or receptors to ligands?
High conc. of receptors to ligands
What is meant by a molecular switch?
It means activation/inactivation by binding of molecules
- activation by phosphorilation
- guanine nucleotide to G protein
What are the 6 steps to signal transduction?
1) recognition of signal
2) transduction (extracell. message to intracell)
3) transmission of second messengers
4) modulation of an effector (altering enzyme activity)
5) appropriate response
6) termination of response
Explain the activation of a G protein coupled pathway acting via adenylate cyclase (Gi/Gs)
ligand binds = conformational change of receptor. The Ga subunit binds to G protein and releases GDP, binds GTP. Gy and Gb components dissociate. G protein active until GTP is hydrolysed.
Active G protein activates adenylate cyclase allowing ATP –> cAMP
cAMP = secondary messenger: activates PKA to activate other certain enzymes
How to adrenaline and prostaglandin act antagonistically in terms of G proteins?
Both act on adenylate cyclase
adrenaline activates it
prostaglandin inhibits it
They bind to two different G proteins (Gi and Gs) but have the same second messenger.
How does cholera toxin act with G proteins?
The bacterium secretes a toxin that can form a very similar activator to adenylate cyclase as G protein. Decays much slower so pathway not turned off.
In gut adrenaline to G protein receptor - adenylate cyclase activation = H2O and chloride secretion (with cholera this continues) = diarrhoea and dehydration
Give adrenaline antagonist
What type of G proteins act via phospholipase C? What are the second messengers?
Gq proteins
Activation of phospholipase C = activation of IP3 and DAG
IP3 = intracell Ca2+ release
Ca2+ + DAG = protein kinase C activatiom
How are calmodulin and protein kinase C linked?
Protein kinase C subunit = calmodulin
if binds with Ca2+ = more catalytic efficiency/accelerating protein
Can the Gyb subunit have a role?
Yes - while parasymp. ACh at the heart causes Gi protein activation, Gyb goes on to open K+ channels aiding in depolarisation - slowing of heart
Explain the role of G proteins and NO signalling to increase blood flow
ACh/bradykinin/adenine nucleotides –> Gq at vascular endothelial cell –> IP3 –> Ca2+ and calmodulin
Ca2+ and calmodulin activate NO synthase = NO production
NO out od endothelial cell –> adjacent smooth muscle and activates guanylyl ciclase –> cGMP = phosporylation of muscle proteins = relaxation = vasodilation and increased blood flow
What is the difference between a receptor tyrosine kinase and a tyrosine kinase linked receptor?
- receptor tyrosine kinase: receptors themselves are protein kinases - cross-phosporilate with dimerisation then phosphorylate tyrosine residues on intracell. enzymes/proteins
- tyrosine kinase linked receptor: don’t have intrinsic enzyme activ bind/dimerise first then bind cytoplasmic tyrosine kinase -> phosphorylate target proteins