Physiology Facts

PHYSIOLOGY FACTS

• Cushing syndrome is a disorder characterized by obesity due to hyper secretion of glucocorticoids.
• Conn’s syndrome is primary aldosteronism.
• Addison’s disease is chronic adrenal insuffiency.
• Hormones of Adrenal medulla (Catecholamines) are
• Adrenaline or epinephrine
• Noradrenaline or norepinephrine
• Dopamine
• Pheochromocytoma is a condition in which there is excessive secretion of catecholamines.
• Melatonin is secreted by parachymal cells of pineal gland, acts on gonads.
• Severe stress can raise ACTH and cortisol level by 20 folds.
• Fetal lung maturation depends on increased fetal Cortisol just before birth.
• Human prolactin causes synthesis of milk in the female breast.
• The half life of circulating growth hormone in humans is 20 to 30 minutes.

BLOOD

• Blood is a connective tissue in fluid form.
• Blood is 5 times viscous than water.
• Blood cell count is greater in children than adult.
• RBC is microcytic in iron defiency anaemia, prolonged forced breathing & increased osmotic pressure.
• RBC is macrocytic in megaloblastic anaemia, muscular exercise & decreased osmotic pressure in blood.
• Punctate basophlism is seen in lead poisoning.
• Goblet ring is seen in certain types of anaemia like malaria.
• Red cell vol. can be determined by radio isotope 51 Cr.
• Cyanosis appears when the reduced Hb cone, of the blood in the capillaries is more than 5 gm/dl.
• In vitro, coagulation is initiated by factor XII.
• Life of RBC's in adult human body is 120 days.
• Average life span of RBC in a newborn is 100 days.
• Average life span of RBC in transfused blood is 90 days.
• Life span of transfused platelets is 4 days.
• Life span of platelets is 9-12 days.
• Complete erythropoiesis occurs in 7 days.
• Erythropoiesis occurs in
• In first trimester RBC's are formed in Yolk sac. While in second trimester liver is the main organ. Third trimester in liver & bone marrow.  
• Upto age of 5 – 6 yrs – red bone marrow of all bones.
• 6 – 20 yrs – red bone marrow of all bones & all membranous bones.
• After 20 yrs – all membranous bones & ends of long bone.
• Hb starts appearing in intermediate normoblastic stage of erythropoiesis.
• Nucleus disappears during late normoblastic stage.  
• Factors needed for Erythropoiesis: erythropoietin, thyroxine, interleukins 3, 6, 11, stem cell factors, Vit B, C & D. (maturation factors Vit B₁₂ & folic acid).
• The iron remains in ferrous state.
• The affinity of Hb for CO₂ is 20 times more than for O₂.
• The affinity of Hb for CO is 200 times more than its affinity for O₂.
• Adult Hb consists of 2 alpha & 2 beta chains.
• Fetal Hb consist of 2 alpha & 2 gamma chains.
• In sickle cell anemia, the 2 alpha chains are normal but 2 beta chains are abnormal.
• In Hb C, beta chains are abnormal.
• Bilirubin is the final product formed from the destruction of Hb.
• Total quantity of the iron in the body is 4gm.
• 1 mg of iron is excreted every day through faeces. 
• Normocytic normochromic anaemia is seen in aplastic aneamia.
• Marcocytic normochromic anaemia seen in folate deficiency, Vit B₁₂ & hypothyroidism.   
• Pernicious anaemia or addsion's anaemia is marcocytic normochromic anaemia.
• Microcytic hypochromic is seen in iron deficiency, thalassemia, heamoglobinopathies & heamolytic anaemia.
• ESR decreases in allergic conditions, sickle cell anaemia, polycythemia & afibrinogenemia.

	Character	Normal
1.	ESR	Male: 3 – 7 mm / hr Female: 5 – 9 mm / hr
2.	PCV (Packed cell volume) (Hematocrit)	Male: 40 – 45 % Female: 38 – 42 %
3.	MCV (Mean corpuscular volume)	90 cuµ (78 – 90 cuµ)
4.	MCH (Mean corpuscular Hb)	30 pg (27 – 32pg)
5.	MCHC (Mean corpuscular Hb Conc.)	30% (13 – 38%)
6.	Colour index	1 (0.8 – 1.2)
7.	WBC	4000 – 11,000 / cmm
8.	D.C Neutrophils Eosinophils Basophils Monocytes Lymphocytes	50 – 70% 2 – 4 % 0 – 1 % 2 – 6% 20 – 30 %
9.	Platelet count	2,50,000( 2 lakhs – 4 lakhs)
10.	Bleeding time	3 – 6 min
11.	Clotting time	3 – 8 min
12.	Prothrombin time	12 sec
13.	Activated partial thromboplastin time(APTT)	25 – 40 sec
14.	RBC Adult male Adult female Birth	4 – 5.5 millions / mm3 5 millions / mm3 4.5 millions / mm3 8 – 10 millions / mm3
15.	Heamoglobin Adult male Adult female New born	14 – 18 gm / dl 12 – 16 gm / dl 16 – 22 gm /dl
16.	RBC Diameter	7.5 µ
17.	Blood volume	5 liters

• Granulocytes are neutrophils, eosinophils & basophils.
• Agranulocytes are monocytes & lymphocytes.
• Monocyte is the largest lymphocyte.
• In hemophilia clotting time is prolonged in presence of normal bleeding time.
• Christmas disease occurs due to deficiency of factor IX.
• Clotting factors

Factor I	Fibrinogen
Factor II	Prothrombin
Factor III	Thromboplastin
Factor IV	Calcium
Factor V	Pro accelerin (labile factor)
Factor VI	No such factor
Factor VII	Stable factor
Factor VIII	Anti hemophilic
Factor IX	Christmas
Factor X	Stuart-power
Factor XI	Plasma thrombplastin antecedent
Factor XII	Hegman (Conduct)
Factor XIII	Fibrin stabilizing factor (Fibrinase)

• Blood group:

Group	Antigen in RBC	Antibody in serum
A	A	Anti – B (β)
B	B	Anti – α
AB	A & B	No anti body
O	No antigen	Anti A & Anti B

• Universal recipient are Blood Group 'AB because it does not contain either Anti A ab or anti B ab.
• Universal donor is Blood Group "()" because it docs not contain either A or B agglutinogen (antigen).
• Commonest blood group is O.
• Diseases associated with blood groups:
• Group A – C.A stomach
• Group O – duodenal ulcer
• Normal basic acid output is 5-10 mmol/hour.
• Blood is stored in the blood bank at 4⁰C.
• The number of iron Heme in one Hb molecule is 4.
• The number of O₂ molecules carried by one Hb molecule is 4.
• Mean corpuscular diameter is 7.5 nm.
• Maximum concentration of Hb normally found in RBC's is 34%.
• In arterial blood, saturated Hb with 02 is 97%.
• Thromboxane A₂ is synthesized by platelets and promotes vasoconstriction and platelet aggregation.
• In sickle cell anemia, valine is substituted for glutamic acid.
• Platelets are derived from megakaryocytes.
• Pus contains — Dead neutrophils, macrophages and necrotic tissues.
• Cardiac output in anemia is above normal while in polycythemia is about normal.
• Agglutinins are either IgM or IgG.
• In Erythroblastosis fetalis, mother is Rh-, father is Rh+, foetus is Rh positive.
• Hapatoglobin is a plasma protein responsible for carrying free Haemoglobin.
• Usual anticoagulant used for transfusion is a citrate salt.
• Earliest feature of iron deficiency anemia is decreased serum ferritin.
• Arneth count is used in the determination of the percentage distribution of different types of neutrophils on the basis of no: nuclear lobes.
• Wilson’s disease is due to decrease in caeruloplasmin.

EXCRETORY SYSTEM

• Hormones secreted by kidney are erythropoietin, thrombopoitein, renin & 1, 25 dihydroxy cholecalciferol.
• 1 kidney contains about 1 – 1.3 millions nephrons.
• Ratio of corical nephrons to Juxtamedullary nephrons 85: 15.  
• The GFR of average sized normal man is approximately 125 ml / minute or 180 liters / day.
• At the rate of 125 ml/min, the kidneys filter an amount of fluid equal to 4 times the TBV, 15 times the ECF vol. and 60 times the plasma volume.
• 1 – 1.5 liters of urine formed / day.
• Urine osmolality in diabetes insipidus is 300 mmol/L.
• Normal protein excretion is 50 -150 mg%.
• The quantity of water lost as sweat per day is 600-800 C.C
• Normal urea clearance is 44 ml/min.
• Renal blood flow is 25% of cardiac output (1300 ml blood/min).
• Total length of distal convoluted tubule is 5 mm.
• Glomerulus membrane permits the passage of substances upto 4 nm and almost totally excludes substance with size greater than 8 nm.
• Each glomerulus is a net work of approximately 50 parallel capillaries.
• Urinary osmolality in diabetes insipidus is 300 m mol/Lit.
• Glucose and amino acid are absorbed in proximal convoluted tubules by secondary active transport or sodium Co-transport.
• Descending limb of thin segment of loop of Henle is freely permeable to water.                                                                   
• Areas impermeable to water — ascending limb of thin segment thick segment of loop of Henle. Proximal half of convoluted tubule.
• Areas impermeable to urea — Distal convoluted tubule & cortical portion of collecting tubules.
• Substances completely reabsorbed in PCT — Glucose, proteins, amino acids, vitamins, acetoacetate.
• Substances partially absorbed in PCT—Na. K, Cl (7/8 reabsorbed in PCT).
• Substances secreted in PCT — H+, PAH (para amino hippurate). creatinine.
• H+ are actively secreted in proximal tubules, distal tubules, collecting ducts.
• Hyperosmilality in the interstitum is the prerequisite for excretion of concentrated urine.
• Urea is reabsorbed from inner meduallary collecting ducts only in presence of ADH.
• K+ is actively secreted in Late Distal tubules and Collecting ducts.
• Macula densa is the epithelial cells of the distal tubule that comes to contact with the arterioles.
• Juxtaglomerular cells produce renin.
• Renin acts on angiotensinogen & convert it into angiotensin I. 
• Renal threshold for glucose is reduced in renal glycosuria.
• Creatinine clearance represents GFR.
• Clearance test for renal function includes inulin clearance, creatinine clearance & PAHA test.
• PAHA test is performed to assess renal blood flow.
• Micturition is primarily a spinal reflex.
• Thick ascending loop of  henle is impermeable to water. 
• Majority of sodium absorption occur  in the proximal tubule.  

Character	Normal
pH	4. 5 – 6
Volume	1000 – 1500 ml / day
Specific gravity	1.010 – 1.025

MALE REPRODUCTIVE SYSTEM

• Average pH of semen is 7.5. 
• Life span of spermatozoa within the female genital tract is upto 24 hours.
• Speed of human sperm in female genital tract is about 3 mm/min.
• Male sex hormones are called the androgens (secreted by leydig cells); testosterone, dihydro testosterone & androstenedione.
• Mullerian ducts gives rise to female accessory sex organs such as vagina, uterus & fallopian tube.
• Wolffian duct gives rise to male accessory sex organs such as epididymis, vas deferens & seminal vesicles.
• Fetal testes begin to secrete the testosterone at about 2^nd to 4^th month of embryonic life.
• The secretion from seminal vesicles contains fructose, phophorylcholine, fibrinogen, ascorbic acid, citric acid, pepsinogen, acid phosphatase & prostaglandin.
• Fructose & citrate acts as fuel for the spermatozoa.
• Prostatic secretion is rich in enzymes, fructose & citrate.
• Androgen appears to be essential for spermatogenesis. Whereas FSH is required for spermatic maturation.
• Testes do not produce fructose.(seminal vesicle)
• Sertoli cells provide nutrition to the developing sperm; secrete oestrogen & hormone binding proteins.
• Testosterone is synthesized from pregnanolone.
• Testosterone stimulates the process of spermatogenesis, also necessary for the formation of secondary spermatocyte from primary spermatocyte.
• Growth hormone is essential for the general metabolic processes in testis.
• Male sex hormone is secreted mainly by interstitial cells of Leydig.
• Development of male sex organ in fetal life depends on testosterone produced under the influence of HCG.
• Testosterone circulates in Combination with Gonadal steroid binding globulin.
• Hormone used for treating osteoporosis in old age — Testosterone.
• In males FSH promotes spermatogenesis by enhancing the transport of Testosterone to seminiferous tubules and androgen binding protein synthesis from sertoli cells.

  

FEMALE REPRODUCTIVE SYSTEM

• During menstrual period, upto 20 gm of protein may be lost.
• Quantity of blood expelled during normal menstral cycle is 40 ml (approx) & serous – 35 mls.
• FSH level is high in post menopausal women.
• Ovarian hormones are estrogen and progesterone
• Ovulation occurs on the 14^th day of menstrual cycle in a normal cycle of 28 days.
• Oxytocin causes contraction of smooth muscles of uterus & enhances labour.
• Hormones secreted are HCG, Oestrogen, progesterone & human chorionic somato mammo tropin.
• Relaxin is a hormone secreted from the maternal ovary during the later periods of pregnancy.
• Biological test for Pregnancy can be performed only after 2 – 3 weeks of conception. 
• LH is concerned with follicle maturation and ovulation.
• Menopausal hot flushes are due to LH surge.
• Estrogen increases the secretion and ciliary beating in fallopian tubes.
• Estrogen changes the cuboidal lining of vagina to stratified.
• Estrogen changes the break down of glycogen into lactate in vagina.
• Estrogen initiates breast development.
• Estrogen causes early epiphyseal closure.
• Estrogen causes water retention.
• Important function of progesterone is to promote secretory changes in endometrium.
• Progesterone is the hormone for maintenance of pregnancy.
• Progesterone inhibits ovulation.
• The most important function of progesterone is to promote secretory changes in endometrium.

  

WATER & ELECTROLYTE / ACID-BASE BALANCE

• In human beings the total body water varies from 45 – 75 % of body weight.
• Total water in the body is about 40 liters. (ICF forms 55% & ECF forms 45%).
• The volume of interstial fluid is about 12 liters.
• The volume of plasma is about 2.75 liters.
• Osmolality is the measure of a fluid’s capability to create osmotic pressure, also called as osmotic conc. of a solution.
• Osmolarity is the no: of particles / per liter of solution.
• Isotonic solutions are having same effective osmolality as body fluids. Eg: 0.9% Nacl solution & 5% glucose solution.
• The insensible water loss from the body is about 600 to 800 ml. per day.
• The quantity of water lost as sweat per day is 600 – 800 C.C.
• The normal pH of plasma is 7.4
• Acidosis is pH  below 7.38
• Alkalosis is pH above 7.42
• Respiratory acidosis: primary excess of carbonic acid
• Due to hypoventilation as in respiratory diseases & neural diseases.
• Metabolic acidosis: primary deficiency of bicarbonate
• As in lactic acidosis, diabetic ketoacidosis, uremic acidosis & diarrhea.
• Respiratory alkalosis: primary deficiency of carbonic acid
• Due to hyperventilation as in hypoxia, neural diseases & psychological conditions.
• Metabolic alkalosis: primary excess of bicarbonate
• As in vomiting & treatment with diuretics.