Category Archives: Physiology

GIT hormones,their actions and sites of action.

Posted by on August 29, 2011 1 comment

Cholecystokinin(CCK) Secreted from I cells Acts on GB and pancreas Increase enzyme secretion Increase contraction Gastro Intestinal Peptide(GIP) Secreted from K cells Acts on Pancreas Increase insulin Decrease fluid absorption Gherlin Secreted from stomach Increase food intake Increase GH secretion …

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Hormone secreting cells of anterior pituitary

Posted by on June 23, 2011 No comments

Acidophil cells Somatotroph- Growth Hormone Lactotroph – Prolactin Basophil cells Corticotroph -  ACTH Thyrotroph – TSH Gonadotroph – FSH

Physiology of respiration, respiratory centres, effects of transection of brainstem.

Posted by on May 4, 2011 No comments

Human respiration is controlled by two mechanisms. Voluntary control Automatic control Voluntary control of respiration is by Cerebral cortex.Voluntary control is needed for respiration at one’s will as in whistling,singing etc. Automatic control of respiration is via the Pontomedullary centers …

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Hormones and neurotransmitters affecting feeding and satiety.

Posted by on April 28, 2011 No comments

Feeding and satiety centre in hypothalamus is modulated by several hormones and neurotransmitters. Since this one is a bit confusing it requires lots of revision. Orexigenic(Increase feeding) Neuropeptide Y. Agouti Related Protein (AGRP). Melanin Concentrating Hormone(MCH). Orexins A and B. …

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Kussmaul’s,Cheyne Stoke’s and Bitots breathing

Posted by on March 16, 2011 1 comment

Kussmaul’s breathing/Acidotic breathing Typically seen in metabolic acidosis Characterized by rapid and deep breathing due to stimulation by increased H+ concentration Causes Metabolic acidosis Diabetic keto acidosis Renal failure Cheyne stokes breathing Respiration shows alternate waxing and waning of tidal …

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Resting Membrane Potential

Posted by on March 7, 2011 No comments

RMP is the potential difference between the inside of a cell and outside.RMP is maintained by K+ ion. RMP of neuron   -70mV RMP of smooth muscle -50mV RMP of cardiac muscle  -90mV RMP of skeletal muscle  -90mV Changes in Na+ …

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Renal Tubular acidosis

Posted by on December 20, 2010 No comments

Type I RTA DCT- H+ secretion Low Urine pH cannot be reduced<5.5 even by NH4Cl Type II RTA PCT -  HCO3 reabsorption Low Fanconis syndrome-Swan neck PCT Type III RTA Autosomal recessive Carbonic Anhydrase defect Type IV RTA DCT- H+/K+ …

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Obstructive Vs Restrictive Lung disease

Posted by on December 20, 2010 No comments

Obstructive lung disease TLC – Increased RV-Increased VC- Decreased FEV1/FVC- Decreased Examples Bronchiolitis Asthma Chronic Bronchitis Bronchiectasis Emphysema Cystic fibrosis Restrictive Lung disease TLC – Decreased RV- Decreased VC- Decreased FEV1/FVC- Increased Examples Sarcoidosis Idiopathic Pulmonary Fibrosis Pneumoconiosis Diaphragmatic Weakness …

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Lung Volumes

Posted by on December 20, 2010 No comments

Total Lung Capacity(TLC)- Volume of air in lungs after maximal inspiration Residual Volume(RV)-Volume of air in lungs after maximal expiration Vital capacity(VC)- TLC-RV Forced Expiratory volume1(FEV1)-Volume of air forcibly expired in first secons Peak Expiratory Flow Rate(PEFR),Maximal Mid Expiratory flow …

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Respiratory failure types

Posted by on December 20, 2010 No comments

Type I Respiratory failure Arterial Hypoxia Due to oxygenation failure PO2- Low ,PCO2- Normal or Low PAO2-PaO2 gradient- Increased eg:ARDS,Pulmonary HTN,ILD,Pneumonia,Pulmonary Edema. Type II respiratory failure Arterial Hypercapnia Due to Ventilatory failure PO2-Low, PCO2-High PAO2-PaO2 gradient-Unchanged Eg:Myasthenia,GBS,MS,ALS,IC bleed,Polio,Narcotic overdose Type …

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Sensory pathways

Posted by on December 17, 2010 No comments

Muscle spindle

Posted by on December 15, 2010 No comments

Gonadal hormones.

Posted by on November 23, 2010 No comments

Inhibin Secreted by sertoli cells in males and granulosa cells in females. Inhibits FSH from ant pituitary Activin Secreted by sertoli cells in males and granulosa cells in females. Stimulates FSH secretion. Relaxin Secreted in females by corpus luteum and …

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Maintenance of Calcium balance

Posted by on November 23, 2010 No comments

Parathormone,Vit D and Calcitonin act together to maintain calcium homeostasis. Parathormone(PTH) Secreted when serum calcium falls. Increase calcium levels by: Promoting bone resorption Increased calcium absorption from intestine(via vit D) Increased reabsorption of Calcium from renal tubules.(Phoshate reabsorption reduced) Overall …

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Water reabsorption in kidneys

Posted by on November 23, 2010 No comments

65% water reabsorption takes place in PCT. Water reabsorption is coupled with sodium reabsorption. Bulk of water reabsorption is secondary to sodium reabsorption. Obligatory water reabsorption Independant of plasma osmolality/water balance. Occurs in PCT. Water reabsorbed isoosmotically and independant of …

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EEG waves

Posted by on October 29, 2010 No comments

EEG has four types of waves alpha,beta,theta and delta. Consider a  family where mother has passed away leaving 3 children in the protection of father.The father will be the head of family(consider him as alpha), next comes the son who …

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Anion Gap and acidosis

Posted by on October 29, 2010 No comments

Anion Gap is of 2 types, plasma Anion gap and urinary anion gap Plasma Anion Gap Plasma Anion Gap refers to the amount of unmeasured anions present in the plasma. Calculated by:[ Na+]     -     [Cl-]+[HCO3-]  or [Na+] + [K+] – …

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Cardiac Cycle

Posted by on October 12, 2010 No comments

Total duration of cardiac cycle= 0.8 S Ventricular systole- 0.3S Ventricular diastole-0.5S Atrial systole- 0.1 S Atrial Diastole- 0.7 S Stroke volume=70-80ml EDV—-130ml ESV=EDV-SV=130-70=60 ml is residual volume Contraction starts in the RA and proceeds in the clockwise direction,ie RA—>LA—>LV—>RV …

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Cardiac conduction and anomalies

Posted by on October 12, 2010 No comments

Resting membrane potential is  -80 to -100mv Phases of cardiac muscle contraction Phase 0- Na+ Influx Phase I- Initial rapid depolarization Transient K+efflux Phase II- Plateau phase Calcium efflux Phase III and IV- K+ efflux, delayed and inward rectifying K+ …

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Methods of measuring body fluid volumes

Posted by on September 30, 2010 No comments

60% of TBW is water- 20% ECF and 40%ICF Out of 20% ECF- 15% is Interstitial fluid and 5% is plasma. Total blood volume is 8% including plasma +cells. Method’s to measure. Plasma volume Evans blue-T1824 Serum albumin labelled with …

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Hypoxia types

Posted by on September 29, 2010 No comments

Hypoxic Hypoxia Due to inadequate PO2 in blood. Anemic Hypoxia Due to quantitative or qualitative deficiency of Hb. Eg: Severe anemia, CO poisoning. Stagnant/circulatory hypoxia. Due to circulatory failure. PO2 is normal Histotoxic Hypoxia PO2 is normal. Due to failure …

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Erlanger Gasser classification of nerve fibres

Posted by on September 29, 2010 No comments

Mammalian nerve fibers divided into 3 groups,A,B,C. Group A fibers are the thickest and Group C fibers the thinnest. Susceptibility to Pressure,Local anaesthetics and Hypoxia. From most susceptible to least: Pressure – ABC Local anaesthetics-CBA Hypoxia-BAC. Mnemonic: ABC PHC A …

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Clotting Factors and clotting disorders

Posted by on September 16, 2010 No comments

I-Fibrinogen II-Prothrombin III-Thromboplastin IV-Calcium V-Proaccelerin,labile factor VI-No factor VII-Stable factor,proconvertin VIII-Anti Hemophilic Factor A,PTC IX-Anti Hemophilic Factor B,Christmas factor X-Stuart prower factor XI-Anti Hemophilic factor C,PTA XII-Hageman Factor,Glass factor XIII-Laki Lorand factor,Fibrin Stabilizing Factor HMW Kininogen-Fitzgerald factor Pre Kallikrein-Fletcher factor …

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Apocrine,Holocrine and Eccrine glands

Posted by on September 16, 2010 No comments

Apocrine glands Apical parts of the glands shed off following secretion eg:Atypical Sweat glands,ceruminous glands,Glands of Moll,mammary glands. Holocrine glands WHOLE part of the gland is destroyed following secretion eg:Sebaceous glands Eccrine glands/Merocrine/Epicrine Glands remain intact(exocrine glands). Majority of sweat …

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Jugular Venous Pressure.

Posted by on September 16, 2010 No comments

  What does waves in JVP represent? The upward deflections are : “a” (atrial contraction) “c” (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumic systole) “v”= atrial venous filling. The downward deflections of the wave …

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DCT and K+ Secretion

Posted by on September 16, 2010 No comments

In distal tubule of the Kidney: K+ is secreted primarily  in response to Na+ reabsorption. So when amount of Na+ reaching distal tubule is less, less amount of K+ will be secreted. In metabolic acidosis,  H+ is excess and it …

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Starlings equation and starlings forces.

Posted by on September 16, 2010 No comments

Image via Wikipedia Starling equation is: ([Pc − Pi] − σ[πc − πi]) is the net driving force, Kf is the proportionality constant, and Jv is the net fluid movement between compartments. By convention, outward force is defined as positive, …

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Troponin and tropomyosin.

Posted by on September 16, 2010 No comments

Image via Wikipedia Troponin Troponin is a complex of three regulatory proteins. Troponin T-Attaches troponin complex to Tropomyosin Troponin I-Binds troponin complex to actin Troponin C-Calcium binding troponin Tropomyosin Covers the sites where myosin heads bind actin. Troponin-Tropomyosin complex inhibits …

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Lewis triple response

Posted by on September 16, 2010 No comments

Lewis triple response is the characteristic three part response that develops when a line is made by a pointed object(a key)on the skin.It is produced due to the release of histamine, the components of this triple response are: 1.Red reaction-red …

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Sensations carried by spinal cord.

Posted by on September 16, 2010 No comments

Columns in the spinal cord and the sensations carried by these columns have been a great headache to me.But when I learned to associate with a back massage it became so easy. Posterior/Dorsal Column Sensations Fine touch and pressure/Discriminative touch …

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