Page 1 of 4: List: High yield notes for Physiology

watchman22 · Credits: 9510 My Scrapbook

here r some topics based on previous mcqs....

1.BODY COMPOSITION:-
in an average young adult male,
18% of body weight is protein & related substances,
7% is mineral
15%is fat..
remaining 60% is water
2/3rd is intracellular & 1/3rd is extracellular...
among 1/3rd extracellular:-1/4th is in vascular system..
& 3/4th as interstitial fluid.

reference :-ganong

watchman22 · Credits: 9510 My Scrapbook

ionic composition:-
ECF ICF
sodium ion:- 142mEq/L 10mEq/L
Potassium ion:- 4mEq/L 140mEq/L
calcium ion:- 2.4mEq/L 0.0001mEq/L
Mg ion :- 1.2mEq/L 58mEq/L
chloride ion:- 103mEq/L 4mEq/L
bicarbonate ion:- 28""/L 10mEq/L
phosphates:- 4mEq/L 75mEq/L
sulphates:- 1mEq/L 2mEq/L
Glucose 90mg/dl 0-20mg/dl
amino acids:- 30mg/dl 200mg/dl

watchman22 · Credits: 9510 My Scrapbook

Erlanger & gasser's classification of nerve fibers:-
fibre type:-A,B & C.
*** Fibre A & B are myelinated while C is unmyelinated.
**Fibre A is subdivided into:-
1.alpha
2.beta
3.gamma
4.delta
based on diameter & conduction velocity..
**** A alpha maximum diameter & maximum conduction velocity.

watchman22 · Credits: 9510 My Scrapbook

cholinergic receptors distribution:-
Cholinergic receptors can be divided into two types, muscarinic and nicotinic, based on the pharmacological action of various agonists and antagonists.

1. Nicotinic :-found in N-M junction
Autonomic ganglia
& CNS.
2.Muscarinic:-
M1:-Cortex,Hippocampus
M2:-heart
M3:-Exocrine glands,GI tract
M4:-Neostriatum
M5:-substantia nigra.

***In smooth muscles M2,M3,& M4 type muscarinic receptors are found.

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Sensory receptors for pain:-
When sensory nerve fibers are exposed to extremes, they signal pain. Pain receptors are also called nociceptors.

Two types of sensory nerve fibers transmit signals that the brain interprets as pain.

* Aδ ("A-delta") fibers
o These are thinly-myelinated.
o They transmit signals rapidly that are associated with acute pain. This is "good pain" because it warns you to do something to take care of the problems, e.g., a hot saucepan.
* C fibers
o These are unmyelinated and thus conduct impulses slowly.
Their activation is associated with diffuse, dull, chronic pain. This is "bad pain" because it cannot be alleviated simply by removing the stimulus. It is pain generated by such things as damaged tissue or pain that remains after the stimulus that caused acute pain has been removed

watchman22 · Credits: 9510 My Scrapbook

retina:-some facts..
**** Cones are more in centre & decreases towards periphery cones respond to bright light & role in color vision.
Fovea centralis:-only cones (max. visual acuity)
macula lutea:- cones > rods (photopic vision)
blind spot:-no rods no cones.
in periphery:-rods> cones (scotopic vision)
Thinnest part of retina:-fovea centralis.

watchman22 · Credits: 9510 My Scrapbook

The human cerebral cortex is 2-4 mm (0.08-0.16 inches) thick and plays a central role in many complex brain functions including memory, attention, perceptual awareness, "thinking", language and consciousness.
The surface of the cerebral cortex is folded in large mammals where more than two thirds of the cortical surface is buried in the grooves, called "sulci". The phylogenetically more ancient part of the cerebral cortex, the hippocampus, is differentiated in five layers of neurons, while the more recent neo-cortex is differentiated in six basic layers.

sections:
Occipital lobe - processes vision;
Temporal lobe - processes hearing, speech, language development
Parietal Lobe - processes sensory stimuli
Prefrontal lobe - allows us to plan and rehearse future actions; connected to the limbic area to help regulate emotions
Frontal lobe - area where critical thinking and problem solving occur
Limbic system - controls emotions and long-term memory
Cerebellum - controls automatic movements and balance

watchman22 · Credits: 9510 My Scrapbook

ESR:-erythrocytes sedimentation rate:-some facts:-

Erythrocyte sedimentation rate (ESR) is a nonspecific screening test for various diseases. It is a simple and inexpensive test that measures the distance that red blood cells have fallen after one hour in a vertical column of anti coagulated blood under the influence of gravity.
The amount of fibrinogen (a blood protein) in the blood directly correlates with the ESR.. The use of the ESR as a screening test in asymptomatic persons is limited by its low sensitivity and specificity as it is affected by many variables.
Women tend to have higher ESR values, as do the elderly. Obese people too tend to have raised ESR for some unknown reason though this is not thought to have any clinical significance.

Any condition that increases fibrinogen levels (e.g., pregnancy, diabetes mellitus, end-stage renal failure, heart disease, collagen vascular diseases, malignancy, and chronic infection) may elevate the ESR. In anaemia the ESR rises as the speed of the upward flow of plasma is altered so that red blood cell aggregates fall faster. Macrocytic (larger) red cells with a smaller surface-to-volume ratio also settle more rapidly.

ESR in healthy adults:-
Age<50
Men:- 0-15mm/hr
women:-0-20mm/hr

Age>50
Men:-0-20mm/hr
Women:-0-30mm/hr

*******The ESR remains an important diagnostic criterion only for polymyalgia rhuematica and temporal arteritis.

# The ESR is an inexpensive, simple test of chronic inflammatory activity.
# Indications for the ESR have decreased as the sophistication of laboratory testing has increased.
# The ESR rises with age, but this increase may simply reflect a higher disease prevalence in the elderly.
# The use of the ESR as a screening test in asymptomatic persons is limited by its low sensitivity and
specificity.
# When there is a moderate suspicion of disease, the ESR may have some value as a "sickness index."
# An extremely elevated ESR (>100 mm/hr) will usually have an apparent cause--most commonly infection, malignancy or temporal arteritis.
# A mild to moderately elevated ESR without obvious etiology should prompt repeat testing after several months rather than an expensive search for occult disease.

watchman22 · Credits: 9510 My Scrapbook

*** Stages of iron deficiency & their detectable lab. abnormalities:-
Stage1:-Depleted iron stores:- Low ferritin & absent B.M iron.

Stage2:-Latent iron deficiency:-Low transferrin saturation,Low serum iron,
raised serum transferrin,normal Hb.

Stage3:-Low Hb.

message:-don't forget to read table for normal values & haematological values in deficiency.

watchman22 · Credits: 9510 My Scrapbook

Vit.B12 metabolism:-Vitamin B12 is synthesized only by microorganisms, and in our diets it is supplied nearly exclusively by animal foods. Meat contains adenosyl-, and hydroxycobalamin; dairy products contain methyl-, and hydroxycobalamin. These protein-bound forms of Vit B12 are digested by gastric acid and pepsin so that the Vit B12 is released into gastric juice where it becomes bound to a salivary B12 binding protein (haptocorrin) rather than to gastric intrinsic factor (IF). Secretion of IF from parietal cells is stimulated by the same agents that stimulate acid secretion, but drugs such as omeprazole which inhibit the H+/K+ pump do not block IF secretion. Haptocorrin and IF are not digested by acid-pepsin, but pancreatic proteases can digest haptocorrin, but not IF. Therefore, in the duodenojejunal lumen, Vit B12 is transferred from haptocorrin to IF. The Vit B12-IF complex binds to a specific receptor in the brush border of ileal absorptive cells. The Vit B12-IF complex enters the ileal absorptive cells by endocytosis and Vit B12 is transferred to transcobalamin which exits through the basolateral membrane into portal venous blood.

Hepatocytes secrete Vit B12 into bile and biliary B12 can be reabsorbed by ileal mucosa. This enterohepatic circulation of Vit B12 helps to maintain normal body stores of the vitamin. Patients who have had an ileal resection may become B12-deficient in 2-3 years. Subjects ingesting a Vit B12-deficient diet may require 10-20 years to manifest B12-deficiency because they are able to conserve biliary Vit B12.

Vit B12 is a cofactor for two enzymatic reactions which maintain the supply of methionine and tetrahydrofolate, and which promote the synthesis of succinyl co-enzyme A. Vit B12 deficiency leads to macrocytic anemia, and to neuropsychiatric abnormalities.

Absorption of Vit B12 can be assessed by a Schilling test.

****major site 4 vit.B12 absorption is ileum & that of folic acid is jejunum.

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