Renal Physiology SEQs

Renal Physiology  SEQs 

1.1 List the factors which affect glomerular filtration rate (40)

1.2. Explain how water in the glomerular filtrate is handled by

1.2.1. The proximal tubule (20)
1.2.2. The loop of Henle (20)
1.2.3. The collecting duct (20)

Respiratory SEQs

Respiratory Physiology SEQs

1. Give the brief account of surfactnat

2. Explain the effect of surfactnat deficiency

3. A 60 year old man was admitted to the hospital with shortness of breath. He had a bluish discoloration of the tongue and an increased respiratory  rate tidal volume . His hemoglobin concentration was within the normal range
Explain

•  Bluish discoloration of his tongue
• The physiological basis of increased ventilation 

factors influencing the bronchial muscle tone

Main factors influencing the bronchial muscle tone 

• In general the smooth muscle of the bronchial walls causes bronchodilation during inspiration and bronchoconstrictions during expiration . 

• Autonomic nerve fibers also innervate the bronchial smooth muscle with cholinergic parasympathetic stimulation causing bronchoconstriction and beta adrenergic sympathetic stimulation causing bronchodilation.( Direct control of bronchioles by sympathetic nerve fibers is relatively weak because few of these fibers penetrate to the central portions of the lung . However the bronchial tree is very much exposed to circulating norephinephrine and epinephrine by sympathetic stimulation of the adrenal medulla ) 

infant respiratory distress syndrome (IRDS)

Pathophysiology of infant respiratory distress syndrome (IRDS)

The lungs of the foetus remain collapsed until birth. At birth the infant makes several strong inspiratory efforts and the lungs expand . Surfactant prevent them from collapsing again. But in infants who are born before their surfactant system is functional ,the surfactant deficiency causes the lungs to collapse .(Surfactant is not secreted until between 6th – 7th month of gestation and some it happens even later) This is called infant respiratory distress syndrome ( IRDS ). According to the law of Laplace the smaller the radius the more the tension so in a baby’s alveloli surface

compliance of the lung

What is meant by compliance of the lung and chest wall ?

The change in lung volume per unit change in airway pressure(ΔV/ΔP) is the strechability or the compliance of the lung and the chest wall.( The extent to which the lungs expand for each unit increase in transpulmonary pressure is called their compliance ) Reference Guyton

This is determined by the elastic forces of the lung

• The elastic force of the lung tissue itself

• The elastic force caused by the surface tension of the fluid that lines the inside walls of the alveoli and other lung space.

However compliance depends on the lung volume : an individual with only one lung has approximately half the ΔV for given ΔP.compliance decreased by pulmonary congestion and interstitial pulmonary fibrosis and is increased in emphysema .

main muscle of quiet breathing

Give the main muscle of quiet breathing and deep breathing

Quiet breathing

Inspiration- Diaphragm (75%). External intercostals muscle

Expiration – No muscle involved

Deep breathing
Inspiration – Strnocleidomastoid ,Serratus anterior and Scaleni

Expiration – internal intercostal muscles , rectus abdominis and other anterior abdominal muscle

defense mechanisms of the respiratory tract

What are the defense mechanisms of the respiratory tract ? Describe each one briefly

• Hairs in the nostrils – 

They strain out particles larger than 10 µm in diameter .

• Tonsils and adenoids – 

Most of the remaining particles of this impact on or near the tonsils and adenoids which are large collections of immunologically active lymphoid tissue in the back of the pharynx.

internal and external respiration

What is meant by internal and external respiration ?

• Internal respiration refers to the gas exchange between the cells and their fluid medium and utilization of O₂ and production of CO₂ by the cells
• External respiration refers to the absorption of O₂ and removal of CO₂ from the body as a whole

Physiology of Hypertension

Physiology of Hypertension 

What is hypertension ?

• Sustain elevation of systemic arterial pressure 
• Systolic pressure over 140 / 90 mmHg in adult at least 3 consecutive visits to the doctor 

Types of hypertension

1. Primary / essential hypertension – cause is unknown . Seen in 92 % of the population 
2. The secondary hypertension – cause is known seen in 7 5 of the population 

Cushing reflex

Physiological basis for Cushing reflex

Cushing reflex (Cushing effect, Cushing reaction, Cushing phenomenon, Cushing response)

• Increase systolic blood pressure and reduce heart rate ( bradycardia) due to increased intracranial pressure 

Cerebral blood flow depends on

• Local constriction and dilation of  cerebral arteriols 
• Intracranial pressure 
• Mean arterial pressure 
• Mean venous pressure 
• Viscosity of blood 

valsalva maneuver

Physiological changes in  valsalva maneuver

Valsalva maneuver

•  Forced expiration against a closed glottis

Stage 1

• Due to forceful expiration against closed glottis intrathoracic pressure increase
• Initially increase thoracic pressure transmit to aorta and increase blood pressure

peripheral cyanosis

Physiological basis for peripheral  cyanosis  in hypovolemic shock

Cyanosis

• Dusky bluish discoloration of tissue 
• Due to increased deoxygenated Hb in blood 
• More than 5 g/dl 

Hypovolemic shock

• Inadequate tissue perfusion 
• Due to relative or absolute reduction of cardiac output 
• Hypovolemic shock occurs due to reduction of total blood ( fluid ) volume 

Physiological basis for carotid bruit

Physiological basis for carotid bruit

Laminar flow

• Fluid flows in parallel layers 
• Each layer remains in constant distance form the vessel wall 
• Fluid layer close to the wall has a lowest velocity 
• Fluid layer at the center of a vessel has highest velocity 
• Laminar flow is silent 
• When blood flows in long, smooth straight vessels it flow as laminar flow

Describe the ionic changes which leads to the the action potentials

Describe the ionic changes which leads to the the action potentials
1. In the non conducting tissues
2. In the auto rhythmic cells

Compare and contrast the cardiac muscle and skeletal muscle

Compare and contrast
1. The electrical activity
2. Excitation : contraction coupling
Of the cardiac muscle and skeletal muscle

Explain the physiological basis for generation of action potential in nerve cell

Explain the physiological basis for generation of action potential in nerve cell.

When the drug nicotine is added to the end-plate region of a skeletal muscle,

Explain (a), (b) 

a. When the drug nicotine is added to the end-plate region of a skeletal muscle, it has a stimulating effect on the muscle.

b. The effect of nicotine is blocked when curare is added to the muscle.

Outline the process by which stimulation of a motor nerve produces contraction in a skeletal muscle

Outline the process by which stimulation of a motor nerve produces contraction in a skeletal muscle

Compare cardic and skeletal muscle in view of

Compare cardic and skeletal muscle in view of

1. Structure

2. Action potential

3. Ability for Tetanization

All-or-non law

Explian

1. The ionic basis of nerve action potential

2. All-or-non law

3. How transmission along a myelinated nerve fiber is about 50 tims faster than along an unmyelinated nerve fiber