Physiology

Reference: Guyton 14th; P- 513

Uncal Herniation
Space-occupying lesions from large tumors, hemorrhages, strokes, or abscesses in the cerebral hemisphere can drive the uncus of the temporal lobe over the edge of the cerebellar tentorium, compressing the ipsilateral cranial nerve III (uncal herniation).
Before the herniation these patients experience a decreased level of consciousness, lethargy, poorly reactive pupils, deviation of the eye to a "down and out" position, hyperactive reflexes, and a bilateral Babinski sign (due to compression of the ipsilateral corticospinal tract).
After the brain herniates, the patients are decerebrate and comatose, have fixed and dilated pupils, and eye movements are absent. Once damage extends to the midbrain, a Cheyne-Stokes respiratory pattern develops.

Brain Areas for Control of the Gamma Motor System
The gamma efferent system is excited specifically by signals from the bulboreticular facilitatory region of the brain stem
and, secondarily, by impulses transmitted into the bulboreticular area from the following: (1) the cerebellum; (2) the basal ganglia; and (3) the cerebral cortex.
Because the bulboreticular facilitatory area is particularly concerned with antigravity contractions, and because the antigravity muscles have an especially high density of muscle spindles, the gamma efferent mechanism is believed to be important for damping the movements of the different body parts during walking and running.

Explanation:

Explanations:
The normal range for INR in a healthy person is 0.9 to 1.3. A high INR level (e.g., 4 or 5) indicates a high risk of bleeding, whereas a low INR (e.g., 0.5) suggests that there is a chance of having a clot. Patients undergoing warfarin therapy usually have an INR of 2.0 to 3.0.

Total body water (TBW) is approximately 60% of body weight. Body water is inversely proportional to body fat. The percentage of TBW is highest in new-borns then in adult males and lowest in adult females and in adults with a large amount of adipose tissue.

Average
Range
Total plasma Calcium concentration
2.4 mmol/L,or
4.8 mEq/L or,
9.4 mg/dl
2.2-2.6 mmol/L
8.5-10.5 mg/dl

Treatment of malignant hyperthermia
a.rapid cooling
b. the administration of dantrolene, a drug that antagonizes ryanodine receptors, which inhibits calcium ion release for the sarcoplasmic reticulum and thereby attenuating muscle contraction.

Explanation-
★Thyroid-stimulating hormone (TSH) is secreted by the anterior pituitary. Dopamine, growth hormone–releasing hormone (GHRH), somatostatin, and gonadotropin-releasing hormone (GnRH) all are secreted by the hypothalamus. Oxytocin is secreted by the posterior pituitary. Testosterone is secreted by the testes.
Reference-Guyton & Hall/13rd/P-927 & BRS physiology/6th/P-233/T-7.1

Reference: Ganong 26^th; Figure-2.5

Lateral Rectus Muscle is supplied by Abducens Nerve
 
Functions of Facial Nerve
Main: Motor innervation to muscles of facial expression (SVE)
Others:  1.Taste innervation of anterior two-thirds of tongue and palate (SVA),
               2. parasympathetic innervation of lacrimal, nasal, palatine and salivary glands (except parotid) (GVE),
               3. sensation to parts of auricle and retroauricular region (GSA)

Snell 8th -351

 ABC of Biochemistry 6th - P: 359

Factors regulating NaCl reabsorption from ALH:
1. It is increased by large NaCl load presented to ALH, sympathetic activity, angiotensin II & norepinephrine
2. It is decreased by prostaglandin & loop diuretics

কোন ব্যাখ্যা যোগ হয় নি।

A negative inotropic effect is one that decreases myocardial contractility. Contractility is the ability to develop tension at a fixed muscle length. Factors that decrease contractility are those that decrease the intracellular [Ca2+]. Increasing heart rate increases intracellular [Ca2+] because more Ca2+ ions enter the cell during the plateau of each action potential. Sympathetic stimulation and norepinephrine increase intracellular [Ca2+] by increasing entry during the plateau and increasing the storage of Ca2+ by the sarcoplasmic reticulum (SR) [for later release]. Cardiac glycosides increase intracellular [Ca2+] by inhibiting the Na+–K+ pump, thereby inhibiting Na+–Ca2+ exchange (a mechanism that pumps Ca2+ out of the cell). Acetylcholine (ACh) has a negative inotropic effect on the atria.

Explanation : Functions of the cerebellum-
a. Vestibulocerebellum—control of balance and eye movement.
b. Pontocerebellum—planning and initiation of movement.
c. Spinocerebellum—synergy, which is control of rate, force, range, and direction of movement.

Ref : BRS Physiology 7th edition

Explanation:

Para-aminohippuric acid (PAH) has the greatest clearance of all of the substances because it is both filtered and secreted. Inulin is only filtered. The other substances are filtered and subsequently reabsorbed; therefore, they will have clearances that are lower than the inulin clearance.

Proprioceptive sensations include
•       Position sensations
•       Pressure sensation from the bottom of the foot
•       Sensation of equilibrium
•       Tendon & muscle sensation

Explanation : The center for accommodation lies in frontal eye field (area 8) that is situated in the frontal lobe of cerebral cortex.
Ref : Sembulingam 6th edition (Page- 997)

Reference: Guyton 14th; P- 496

Explanation : Normal duration of synaptic delay is 0.3 to 0.5 millisecond. Synaptic delay is one of the causes for reaction time of reflex activity.
Ref : Sembulingam 6th edition (Page- 785)

Pepsinogen is synthesized from amino acids in the ribosomes attached to endoplasmic reticulum in chief cells. Pepsinogen molecules are packed into zymogen granules by Golgi apparatus. When zymogen granule is secreted into stomach from chief cells, the granule is dissolved and Pepsinogen is released into gastric juice. Pepsinogen is activated into pepsin by hydrochloric acid.

Volitional tests of respiratory include
a- Mouth Pressures (Maximal Static Inspiratory and Expirato Pressure).
b- Sniff Test
c- SNIP Test (Sniff pressure at nose measured )
d- Cough Tests

Common anticoagulants used in laboratory :
1. 3.8% sodium citrate or oxalate 
2. Potassium oxalate
3. Paul Heller's mixture                                   
(1.2 gm ammonium oxalate + 0.8% potassium oxalate+100ml distilled water) 
4. Heparin
5. Warfarin
6. Normal saline
7. Dicumarol
8. EDTA

Oxytocin is secreted from posterior pituitary.

Explanations:
The centrosomes are microtubule-organizing centers (MTOCs) that contain γ-tubulin. The microtubules grow out of this γ-tubulin in the pericentriolar material. When a cell divides, the centrosomes duplicate themselves, and thepairs move apart to the poles of the mitotic spindle, where they monitor the steps in cell division.

Explanation- pH of pancreatic juice is approximately 8.0.
Reference-Ganong physiology/26th/P-454/T-25.3

HCl activates pepsinogen to active pepsin.

Explanation : Pupillary reflexes are classified into three types: 1. Light reflex 2. Ciliospinal reflex 3. Accommodation reflex.
Ref : Sembulingam 6th edition (Page- 994)

Myosin-thick filament

The other cortical cell types are local circuit interneurons and are classified based on their shape, pattern of projection, and neurotransmitter. Inhibitory interneurons (basket cells and chandelier cells) release GABA as their neurotransmitter. Basket cells have long axonal endings that surround the soma of pyramidal neurons; they account for most inhibitory synapses on the pyramidal soma and dendrites. Chandelier cells are a powerful source of inhibition of pyramidal neurons because their axonal endings terminate

exclusively on the initial segment of the pyramidal cell axon. Their terminal boutons form short vertical rows that resemble candlesticks, thus accounting for their name. Spiny stellate cells are excitatory neurons that release glutamate; these multipolar interneurons are located primarily in layer IV and are a major recipient of sensory information arising from the thalamus.

In addition to being organized into layers, the cerebral cortex is also organized into columns. Neurons within a column have similar response properties, suggesting they comprise a local processing network (eg, orientation and ocular dominance columns in the visual cortex).

Explanation :

Ref : Sembulingam 6th edition (Figure- 169.1)

Explanation : Neurons of dorsal and ventral cochlear nuclei in the medulla oblongata form the second order neurons of auditory pathway.
Ref : Sembulingum 6th edition (Page- 1013)

Spinal Nerve:
1.They are 31 Pairs
2. Formed by Union of anterior and Posterior Nerve roots
3.The posterior ramus contains both motor and sensory axons
4. The anterior ramus contains only motor axons

Snell 8th -128

Medial geniculate Body is the-
-Relay station for auditory pulse

Explanations: Glycophorin & anion exchange protein are integral protein of RBC membrane protein.

Movement of the diaphragm accounts for 75% of the change in intrathoracic volume during quiet inspiration. Attached around the bottom of the thoracic cage, this muscle arches over the liver and moves downward like a piston when it contracts. The distance it moves ranges from 1.5 cm to as much as 7 cm with deep inspiration.

Glucocorticoid secretion unaffected
-High potassium intake
-Low sodium intake
-Constriction of inferior vena cava in thorax
-Standing
-Secondary hyperaldosteronism (In some cases of congestive heart failure, cirrhosis, and nephrotic syndrome)

Explanations: ‘O’ group has no antigen & AB group has no antibody.

When hunger contractions occur in the stomach, the person sometimes experiences mild pain in the pit of the stomach, called hunger pangs.

According to the NIH, the following desired values are used to measure an overall lipid profile:

LDL: Less than 160 mg/dL (if you have heart disease or diabetes, less than 100 mg/dL)
HDL: Greater than 40–60 mg/dL
Triglycerides: 10–150 mg/dL

The average blood volume of adults is about 7% of body weight, or about 5 litres. About 60% of the blood is plasma and 40% is red blood cells, but these percentages can vary considerably in different people, depending on sex, weight, and other factors.

Amplitude of pulse pressure in the corta is directly to-

  Stroke volume
  velocity of blood flow
  Elasticity of vessel
  Raised in old age

Bile acid metabolism
1. Site- Liver
2. Compartment- Cytoplasm
3. Rate limiting enzyme- 7-a- hydroxylase
4. No ATP is produced/used


ABC of Biochemistry 6th - P: 205

Hypoparathyroidism leads to hypocalcemia, by decreasing the resorption of calcium from bones. Hypocalcemia causes neuromuscular hyperexcitability, resulting in hypocalcemic tetany. Normally, tetany occurs when plasma calcium level falls below 6 mg/dL from its normal value of 9.4 mg/dL.

Explanation:
Ejection click: an ejection click sound occurs immediately following the first heart sound. The sudden opening of a deformed but mobile aortic or pulmonary valve produces the ejection click.