Fluid and electrolyte balance

Fluid and electrolyte balance 

Body fluid and compartments

Factors affecting total body water 

1) Age - with increasing age total body water level goes down
2) Gender - females have more body water than males
3) Fat content - with increasing Fat level TBW level goes down

lecture note on Hypoxia

lecture note on Hypoxia ( Phsiology )

Hypoxia

Definition:
  Oxygen deficiency at tissue level.
(Anoxia = No oxygen at all left in the tissues)

The four categories of hypoxia

1. Hypoxic hypoxia
2. Anaemic hypoxia
3. Stagnant/ischaemic/hypoperfusion hypoxia
4. Histotoxic hypoxia

partial pressure of gases

1.What is the influence of humidified air , on partial pressure of gases ? 

Air equilibrate with water is saturated with water vapor. The air reaching the lungs is saturated by humidification procedures in the airways . By the additional water vapour component , the percentage of the individual gases are lowered and therefore the partial pressure of them . As the total pressure is the sum of all the partial pressures . The partial pressure of water vapour is 47 mmHg at body temperature , which results in the reduction of PO₂  to 149 mmHg which is 160 mmHg in the absence of water vapour 

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

Formation of pulmonary surfactant

Comment briefly Formation and metabolism of pulmonary  surfactant 

Formation and metabolism of pulmonary  surfactant 

Surfactant is a mixture of dipalmitoilphosphatidylcholine (DPPC), other lipids and proteins .It is produced by type II alveolar epithelial cells . Lamellar bodies, membrane bound organelles containing whorls of phospholipids are formed in these cells and secreted into the alveolar lumen by exocytosis. Tubes of lipid called tubular myelin form from the extruded bodies , which in turn the phospholipid film 

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.

Ventilation

Ventilation

• Total ventilation / respiratory minute volume = Tidal volume (TV) × Respiratory rate (RR)
• Amount of air that reach the alveoli is called alveolar ventilation
• Alveolar ventilation = ( Tidal volume – Dead space volume ) × Respiratory rate
• VA = ( TV – DSV ) ×  RR

Mechanism of respiration

Mechanism of respiration 

At rest

• Chest wall tends to expand , lung tends to recoil 
• Opposing are balanced ; therefore ,negative intra-pleural pressure is developd 

At inspiration

• Active process 
• Main muscle – diaphragam 

Bronchial innervation

Bronchial innervation

	Receptor	Secretions	Bronchial tone
Sympathetic	Beta 2	Increases	Decreseas ( broncho- relaxation )
	Alfa 1	Decreases
Parasympathetic	Muscarinic ( M )	Increases	Increase (broncho constrictions )

Lung volume and capacities

Lung volume and capacities

Tidal volume (TV) 

• Amount of air inhaled or exhaled in one breath during relaxed breathing 
• 500ml 

Inspiratory reserve volume (IRV) 

• Amount of air in excess of tidal inspiration that can be inhaled with maximum effort 
• 3000 ml 

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 

Cardiovascular regulation

Cardiovascular regulation
Systemic regulation 

1.Neural 
Vasomotor center 

Factors affecting vasomotor center

Direct stimulation

• Hypercapnia 
• Hypoxia 

CVS revision note part 5 - Cardiac output

Cardiovascular system  revision note - Cardiac output

Cardiac output = stoke volume(SV) × heart rate(HR)

Cardiac output

• The volume of blood pumped by each ventricle within a unite time ( minute )
• Average = 5l / min
• Normal range = 4-8 l/min

Stroke volume

• The volume of blood pumped by each ventricle per heart beat
• Average = 70ml/ min
• Normal range = 55-100ml/min

CVS Revision part -3 Cardiac cycle

                     CVS Revision part -3  Cardiac cycle

Mechanical events in the cardiac cycle 

1.Late diastole
2.Atrial systole
3.Ventricular systole

a.Isometric ventricular contraction
b.Ventricular Ejection

4. Early diastole

a.protodiastole
b.Isovolumetric ventricular relaxation

CVS revision note part 2 - ECG

                                   CVS revision note part 2 -ECG

                                                          

Understanding ECG

    

•  Body is a volume conductor (offers little resistance to spread of electrical impulse ) 
• Fluctuations of electrical potentials of myocardial cells can be recorded extracellular using electrodes 
• When the sum of theses fluctuations recorded on a moving strip of paper, throughout the cardiac cycle, It is called Electrocardiogram 
•  ECG can be recorded using unipolar or bipolar electrodes 
• Net flow of current is from upper right to lower left side of the body 

Cardiovascular system revision note -1

Cardiovascular system  revision note - introduction 

Cardiovascular system composed of

• Heart – the pump 
• Blood vessels – conducting channels 
• Blood – transport medium 

Functions

• Transport O2 and other substances to tissues 
• Transport CO2 metabolic waste products from tissue for excration 
• Regulation of body temperature 
• Distribute hormones and other signaling molecules to regulate cellular function