Physiology Mock Test

In exercises, various physiological parameters change in order to meet the increased demand for oxygen and nutrients by the muscles. Increased peripheral vascular resistance refers to the narrowing of blood vessels, which leads to increased resistance to blood flow. This is not a parameter that typically changes during exercise. On the other hand, increased blood pressure, increased cardiac output, and increased heart rate are all common responses to exercise as the body tries to deliver more oxygenated blood to the working muscles. Therefore, the correct answer is increased peripheral vascular resistance.

Erythropoietin-Erythropoietrin increases the number of erythropotein sensitive committed stem cells in the bone marrow that are converted to red blood cell precursors and subsequently to mature erythrocytes.

↑ BP arterial receptors reflexly ↓ Heart Rate → bradycardia.
Hypoxia Stimulate vasomotorarea ↑ Systematic arterial pressure
Hypercapxia ↑
Blood supply to vasomotor area 1.Restores the blood flow to the medulla and
↑ 2. ↑ BP & ↑ICT.
↑ICT

Neuromuscular junction
Sequence of events during transmission
Steps in contraction
1. Discharge of motor neurons
2. Release of transmitter (acetylcholine) at motor end plate.
3. Binding of acetycholine to nicotinine acetycholine receptor.
4. Increased Na+ and K+ conductance in end plate
5. Generation of action potential muscle fibres.
6. Inward spread of depolarization along T tubules.
7. Generation of end plate potential.
8. Release of Ca+2 from terminal cisterns of sarcoplasmic reticulum and diffusion to thick and thin filaments.
9. Binding of Ca+2 to troponin C, uncovering myosin binding sites on action.
10. Formation of cross linkages between actin and myosin and sliding of thick filaments producing movements.

Concentration of some ions inside and outside mammalian spinal motor, neurons.
Iron Concentration Equilibrium
(mmol/l of H2O) potential (mv)
Inside cell Outside cell
Na+ 15.0 150.5 +60
K 150.0 5.5 -90
Cl- 9.0 125.0 -70
Resting membrane potential-70 mv.

Coronary vessels are severely compressed during systole. During diastole the cardiac muscle reflaxes and no longer onstruct the blood flow through the left ventricular capillaries so that blood now flows rapidly during all diastole.

During exercise, the body's demand for oxygen and nutrients increases, leading to an increase in heart rate and cardiac output. This allows for more blood to be pumped to the muscles and organs. Additionally, coronary blood flow increases to provide adequate oxygen supply to the heart itself. Venous return, which is the amount of blood returning to the heart, also increases during exercise. However, peripheral vascular resistances, which refer to the resistance to blood flow in the peripheral blood vessels, decrease during exercise to facilitate increased blood flow to the muscles. Therefore, the correct answer is peripheral vascular resistances.

When intra cranial pressure is increased, the blood supply to the vasomotor area is compromised and the local hypoxia capnia increase its discharge. The resultant rise is the systematic arterial pressure (Cushing reflex) tends to restore the blood flow to the medulla and over a considerable range; the blood pressure is raised proportional to the increase in Intra cranial pressure.

Astrocyte foot processes are closely associated with the blood vessels to form the blood-brain barriers oligodendrocytes forms myelin sheath which surrounds axons. Microglia are blood derived non nuclear macrophages.

Ionic Basis of resting membranes potential
K channelks maintain the resting potential.
- Na+ is actively transported out of neurons and other cells.
- K+ is actively transported into cells.
- K+ moves out of cells and Na+ moves in but because of K+ permeability at rest is greater than Na+ permeability.

Trapping of iodine and coupling are inviolved in process of T3 synthesis but not ingestion of potassium iodide.

6 Hormones secreted by anterior pituitary
- Thyroid stimulating hormone TSH.
- Adrenocorticotrophic hormone (ACTH)
- Lutenising hormone (LH)
- Follicle stimulating hormone (FSH)
- Prolactin and growth hormone
ACTH, prolactin and growth hormone are simple polypeptides

In addition to hydrochloric acid, the parietal cells, the gastric mucosa secrete intrinsic factor a 49 K Da glycoprotein that binds to cynacobalamin (Vitamin B12) and is necessary for its absorption from the small intestine.

Shock:-
A syndrome with inadequate tissue perfusion with a relatively or absolutely inadqequate cardiac output.
1. Hypovolemic shoch-fainting, Anaphalyxis, surgery, and fluid due to vomiting or diarrhea.
2. Distriubutine sjoch-fainting, Anaphylaxis, sepsis.
3. Cardiogenic shock- myocardial infarction congestive heart failure. Arrytrhythmias.
4. Obstructive shock- Tension pneumothorax.
Pulmonary embolism
Cardiac tumor
Cardiac tamponade.

C’ wave is the transmitted manifestation of the rise in the atrial pressure produced by the bulging of the tricuspid valve into the atria during isovolumetric ventricular contraction.
‘a’ –wave-atrail systole, ‘v’ wave – rise in atrial pressure before tricuspid valve opens during diastole.

Projection fibres are a type of neural fibres that connect different regions within the brain and spinal cord. They transmit information from one area to another, allowing for communication and coordination between different brain regions. Pyramidal fibres specifically refer to the long axons of pyramidal neurons, which are found in the cerebral cortex and are involved in motor control and cognitive functions. Therefore, the correct answer is projection fibres.

HAPO- High Altitude Pulmonary Oedema
Clinical features- Occur at above 3000 meters.
- Ibcessant dry cough, shortness of breathes, headache, decreased exercise performances, fatilgue and dyspnea at rest chest tightness.
- Later wheexing, orthopnea and hemoptysis may occur.
- Pulmonary edema develops at late stages.
- Pulmonary arterial blood pressure is elevated wedge pressure is normal

“After the aortic and pulmonary valves are closed pressure in the ventricle continues to drop rapidly during the period of isovolumetric ventricular relaxation.”

Triple response
When all the skin is stroked more firmly with a pointed instrument, instead of the white reaction there is reddening at the site that appears in about 10 seconds( Red reaction) wheal- local edema due to capillary permeability flare-redness spreading out from the injury. This three-part response the red reaction. Wheal and flare are called triple response.
Flare:- It is due to axon reflex.
Evidence:- Flare is absent in locally anaesthetized skin and in deneverated skin after the sensory nerves have degenerated

The motor unit
- Each single motor neuron and the muscle fiber it innervates constitutes a motor unit.
- Each spinal motor neuron innervates only one kind of muscle fiber, so that all of the muscle fibre in a motor unit are of the same type