Skeleton of Human

Skeleton of Human

v Skull: Has total 29 bones

·       Total cranial bones : 8

Frontal -1, parietal- 2, temporal-2, occipital-1, sphenoid-1

Ethmoid-1

Middle ear in human is enclosed by temporal bone

·        Total facial bones: 14

Nasals-2, maxillae-2, mandible-1, vomer-1, palatine-2, lachrymal-2, inferior nasal-2, zygomatic (cheek bone) - 2

·        Ear ossicles: 6( 3 in each ear)

·        Single hyoid bone at the base of tongue

·        The joint of skull bone is called suture and the air filled cavities in the skull bone is called sinuses

·        Coronal suture joins frontal and parietal bone

·        Lambdoidal suture joins parietal and occipital bone

·        Squamous suture joins parietal and temporal bone

·        Saggital suture joins two parietal bones

·        Sella turcica for lodging pituitary gland is found in sphenoid bone

·        Mastoid process is found in temporal bone

v Vertebral column:

 Total no vertebra is 33 in infants and 26 in adults. In adult the sacral and coccyx vertebra gets fused

·        Cervical- 7

·        Thoracic- 12

·        Lumbar- 5

·        Sacral- 1(5 in infants)

·        Coccyx- 1(4 in infants)

v Sternum: single piece, flat and has Xiphoid process

v Ribs: 12 pairs

·        True: 7 pairs ( 1^st- 7^th)

·        False/pseudo: 3 pairs ( 8^th,9^th,10^th)

·        Floating: 2 pairs (11^th-12^th)

v Pectoral girdle: total 4 bones : 2 clavicle and 2 scapula

v Pelvic girdle: 2 innominate bones, Innominate= (pubis+ilium+Ischium)

v Fore limbs: total 60 bones(both hands) : humerus-2,radius-2,ulna-2,carpals-16,metacarpals-10 and phalanges- 28

v Hind limbs: total 60 bones(both legs) : femur-2, tibia-2,fibula-2,patella-2,tarsals-14,metatarsals-10,phalanges-28

Note:

·        Total bone in adult : 206

·        Total bone in infant: 213

·        Ligament joins bone to bone and tendon joins bone to muscle

        ¨        Extra knowledge:

·        Clavicle is first bone to ossify

·        Mandible is second bone to ossify

·        Sinuses are the air filled cavity of skull bones.there is 4 sinuses in human, they are: maxillary sinus, frontal sinus, sphenoid sinus and ethmoid sinus. The inflammation of sinus is called sinusitis( pinas)

·        Fontanelle is the membranous space between the cranial bones in infants.

·        Knee joint is largest joint of human body

·        Arthritis is the inflammation od joint

·        Tuberculosis of back bone is called pott’s disease

·        Deficiency of vitamin D in children causes rickets

·        Deficiency of vitamin D in adult causes osteomalacia

·        The decrease in bone mass due to deficiency of calcium is called osteoporosis

·        Osteomyelitis: the inflammation of bone by staphylococcous aureus

·        Gout is the disease of joint caused by deposition of sodium urate crystal in joints

·        Osteosarcoma is the cancer of bone

·        Osteogenesis imperfect : also called brittle bone syndrome is genetic disorder resulting in failuse of ossification of bone

·        Polio caused by picorna virus caused bone deformities in limbs

·        End of long bones are made up of hyaline cartilage

·        Redbone marrow is present on epiphysis of long bone and yellow bone marrow in metaphysis

·        Long bones of mammal consist of Haversian canal. The two haversian canal are joined by volkmans canal

DNA replication

DNA replication

The process of synthesis of DNA molecule from preexisting dna is called dna replication.

DNA replication may occur by following process:

1     1.semi-conservative replication

         2.conservative replication

         3.dispersive replication

Semi-conservative mode of DNA replication

Enzymes involved in semi conservative DNA replication:

Helicase- helicase enzyme breaks the hydrogen bonds formed between bases of nucleotides

Topoisomerase- topoisomerase enzyme breaks and reseals one strand of DNA

DNA polymerase- it connects the nucleotides to form DNA polymer nucleotides. It forms RNA primer in DNA strand which is like a knot formed o thread. Due to its formation, newly formed DNA strands cannot separate.

Ligase- ligase binds the fragments of DNA strand together

Repair enzyme- this enzyme cuts off wrong base of nucleotide and rejoin correct base in newly formed DNA

Process:

DNA replication in  eukaryotes may begin at several points. in replication ,the helicase enzyme breaks the hydrogen bond between the bases of nucleotides. due to breaking of hydrogen bonds of nucleotides, the two strands separate. The process of separation of DNA strands also supported by enzyme topoisomerase. This enzyme breaks and reseals one strand of dna molecule.

Now the bases of DNA strands become exposed and joins with the free nucleotides present in nucleoplasm only in 5’-3’ direction. This process or formation of polynucleotide chain takes place in the presence of enzyme DNA polymerase. The four types of nucleotides are present in nucleus in the form of datp, dgtp; dttp and dctp.THESE molecules are triphosphates and break down into monophosphates damp, dtmp, dcmp and dgmp with the release of energy. These monophosphates nucleotides make hydrogen bonds with the complementary nucleotides of DNA strand.

According to base pairing rule the nucleotides are arranged. As DNA strand formation occurs only in 5’-3’ direction,in on strand of DNA a continuous strand is formed called leading strand ehereas in other strand of DNA,fragments of strands are formed,these fragments are called okazaki fragments named after Japanese scientist okazaki.the strand with okazaki fragments is called lagging strand.

Here,both DNA strands take part in replication process,so they are called as templates.the segments of strands are joined by the help of enzyme ligase.at the beginning of strand formation, RNA primer is formed at the DNA strand and it is due to the enzyme primase.sometime a wrong base maybe linked with the DNA nucleotide. When it occurs,the  repair enzyme replaces the wrong base by correct base.

In the above process,newly formed DNA have one strand of old DNA and one of new formed polynucleotide chain. Hence the process is called as semi conservative process of DNA replication.

It means half of parent DNA is conserved in new formed DNA.

Introduction Kalazar

Kalazar ( leishmania donovani)


Systematic position

Phylum-Protozoa
Class- flagellate
Order- kinetoplostidia
Genus- Leishmania
Species- donovani

The pathogenic flagellate parasite found in reticulo- endothelial system (liver, spleen bone-marrow)

History-
Biologist leishman reported the parasite from London in 1903.Another biologist Donovan reported the parasite in spleen smears of patient in Madras in same year. So the name of parasite became Leishmania Donovani.

Mode of infection - Sand Fly (Phlebotomus argentipes). There are the two types of parasites of the leishmania donovani.

1. Amastigote :

-Found in human
-It is round-oval 2 to 4μm covered by thin pellicle.
-Nucleus is also oval round.
-Kinetoplast (a DNA containing body and mitochondrial structure) lies at right angle to nucleas.
-Axoneme (rhizoplast) a filament extends from kinetoplast to margin of the body.

2. Promastigote:

-Found in sand fly and by culturing.
-It is pear shaped and slender-shaped in maturity.
-Nucleus is more oval.
-Kinetoplast lies transversely near anterior end.
-Axoneme extends outward to forma long flagellum.




Symptoms :

• Recurrent fever intermittent or remittent with often double rise
• loss of appetite, pallor and weight loss with progressive emaciation
• weakness
• Splenomegaly – spleen enlarges rapidly to massive enlargement, usually soft and nontender
• Liver – enlargement not to the extent of spleen, soft, smooth surface, sharp edge
• Lymphadenopathy 
• Skin – dry, thin and scaly and hair may be lost. Light coloured persons show grayish discolouration of the skin of hands, feet, abdomen and face which gives the Indian name Kala-azar meaning “Black fever”
• Anaemia – develops rapidly

 Diagnosis: 

Clinical:
A case of fever of more than 2 weeks duration not responding to antimalarials and antibiotics. Clinical laboratory findings may include anaemia, progressive leucopenia thrombocytopenia and hypergammaglobulinemia

Laboratory:
K39 test

Treatment :
By using drugs like:

• Sodium Stibogluconate
• Pentamidine Isethionate
• Amphotericin B
• Liposomal Amphotericin B
• Miltefosine 

Socially significant disease

    DRUG ABUSE 

Drugs are the chemical substance that modifies one or more functions of living organism.

Drug abuse
Misuse of drug is called drug abuse.

The disease that brings abnormal changes or mental illness due to smoking, drug, alcohol etc known as mental diseases. One percent of world population suffers from mental illness and ten percentages from mild mental disorders. A condition of habit or feeling compelled to take certain drugs is called drug addiction.
Drugs are either depressants or stimulants.
Depressants slow down the activity of brain. Stimulants excite the activity of brain.

Types and effects
i) Tranquilizers and depressants-
These lower the activities of CNS. These do not affect the working efficiency. Examples are- Equanil, Valium (diazepam) calm pose etc. Their excessive use causes addiction.
ii) Narcotics-These are used to free from anxiety (nervous and worried).These produce sleep and relieve
pain. Examples are Opium, Morphine, caffeine and Heroin.
iii) Psychedelic or vision producing drugs-
These effect on sense organ and cerebrum strongly. Individual may see strange colour and sound for nothing. Examples are LSD (Lysergic Acid diethylamide) Marijuana and Hashish.


Effects on health

Depressant and hypnotic:
Depressed brain and deep sleep.
Stimulants: Restless, and BP, heart beat appetite are affected.
Narcotics: Reduce respiratory and cardio-vascular activities, Cause nausea and vomiting. Supress brain activity, anxiety and fever.
Psychedelics hallucinogens: Damage CNS leading to suicide.

Reasons of drug addiction

• curiosity
• Family history
• Peer pressure ( pressure of friend)
• Relief from pain
• To do more work
• Frustration

Control measures

• Hospitalization of sick or addict
• Counseling
• Banning of smuggling of drugs
• Strictly implementation of law
• Education

Alcohol addiction (Alcoholism)

Alcohol is obtained through the fermentation (decaying) of different food ( rice, millets, potati, molasses and fruits) by yeast or fungi.

Two kinds of alcohols
Less concentration- beer, wine etc. these are not distilled.
More concentrated- whiskey, brandy rum gin, vodka, etc. Distilled well

The prolonged use ( long time ) of alcohol causes dependence of body called alcohol addiction or alcoholic. Alcohol is a depressant drug.

Effects of alcoholism (symptoms)

• CNS- loss of sensation, emotional control, visual problems, neuritis ( any projection from cell body) Amnesis (loss of memory)
• Gastrilitis
• Liver is highly affected 
• Increase blood pressure and mal-function of heart
• On kidney- hyper-osmotic ( less concentration) urine 
• Lower the blood sugar level.
• Affect on ovulation and unborn baby in women.
• Cause family and social problems.
• Crimes( rape, kill)

Reasons of alcohol addiction

• feeling of independence
• Frustrations
• To increases confidence
• Social pressure 
• curiosity

Controls
a. Treatment and hospitalization
b. Rehabilitation
c. psychological treatment
d. strict on laws
e. Education

Smoking

Regular consumption of tobacco in different forms (cigarette, chewing) is called smoking.
It is made from leaves of tobacco plant ( Nicotiana tobaccum and N. ristica)

Tobacco smoking contains 4000 different chemicals. Major are nicotine cyanide, formaldehyde, tar, co etc.

Effect off nicotine

1. If nicotine is injected intravenously can kill a human.
2. stimulates the conduction of nerve impulse, secrete adrenaline.
3. BP and heart beat increase
4. Decrease the breathing capacity

Hemp Plant ( cannabis indica c. sativa)
1. Charas- resinc of c. indica
2. Bhang- Leaf and seed of c.indica
3. Marijuana (hashish) - leaves and flowers tops of c. sativa

Effects (short term)
1. Senseless, confusion and fears.
2. Intense in color and sound.
3. BP and heart beat increase.
4. Red eye and dry mouth.

Long term effects

1. cancer- tobacco is carcinogenic c to form cancerous cell). It cause oral cancer and lung cancer
2. Bronchitis- Reduce lung is gaseous exchange capacity.
3. Emphysema- breakdown of wall of alveolar wall during coughing so reduce the gaseous exchange.
4. Heart diseases- Nicotine constrict blood vessel result increase of heart beats.
5. Birth defects- In a pregnant woman it causes 10w birth weight, metal disability and damage of internal organ.
6. Duodenal ulcers, tuberculosis and lack of o2 in blood.

Controls

a. Treatment and hospitalization
b. Rehabilitation
c. psychological treatment
d. strict on laws
e. Education

Osmoregulation and Homeostasis

Osmoregulation  and  Homeostasis

In case of human hypertonic urine is excreted. This minimizes the water loss from their body. The filtrate fluid in Bowman's capsule (isotonic) passes through the tubules of nephrones. Then a large amount of water and solutes are reabsorbed during this course.
During cold month, hypotonic urine is excreted but in warmer month hypertonic urine is excreted due to sweating.

ADH and regulation of water reasbsorption
Antidiuretic hormone (ADH) or vasopressin is the hormone released by posterior part of pituitary gland. The main function of ADH is to increase permeability of distal convoluted tubule (DCT) and collecting duct (CD) due to which reabsorption of water increases. There are two conditions to balance water:

1. When a person takes small amount of water: In this condition large amount of salt is ingested in diet or excessive sweating then solute potential of the body fluids become more negative (Osmotic pressure rises in the blood). The change in the osmotic potential is detected by osmoreceptors in the hypothalamus and carried to the brain. The brain detects such changes in the body and pituitatory gland releases ADH in the blood.
A large amount of water is reabsorbed rapidly from the filtrate into the cortex and medulla and passes back into the blood capillaries to maintain osmotic pressure normal. So that urine becomes highly concentrated and reduced volume of urine is released from kidney. It is generally called anti-diuresis.

2. When a person takes large amount of water: When a person takes large amount of water or little sweating or extremely low salt intake in diet then the solid potential of the blood becomes less negative. (Osmotic pressure becomes low in blood) This condition is detected by osmoreceptors and carried to the brain. It sends the message to the pituitary gland to inhabit the
In absence of ADH walls of DCT and CD are impermeable to water and less water is reabsorbed as the osmotic pressure of filtrate is normal and large volume of diluted urine is excreted. It is generally called diuresis.
The regulation of water by ADH is an example of homeostatic feedback mechanism.

Other functions of kidney
1. Regulation of fluid balance: The kidney controls osmotic pressure of extra cellular body fluids by regulating the amount of water lost from body.
2. Regulation of electrolyte concentrations: The concentration of electrolytes like Sodium, Potassium, Chloride Bicarbonates etc in blood also regulated. It is performed by selective tubular reasbsorption process in proximal tubule.
3. Maintenance of acid-base balance
4. Removal of other substances like mineral salts, iodides, drugs, arsenic and bacteria are recovered of the blood by kidney only.
5. Kidney secretes rennin which is an enzyme but acts as hormone which changes the plasma protein.
6. Kidney secretes erythropoietin which stimulates the formation of RBC.

Homeostasis

The regulation or maintenance of a constant body fluid or internal environment is called homeostasis. The temperature, amount of water and glucose concentration are at almost constant in homeostasis. At the temperature of 37 oC enzymes work perfectly, division of cell and metabolism is also perfect.
The term homeostasis was first put forward by French biologist Claude Bernard in 1859. In 1929, American physiologist Walter Cannon first used the term homeostasis and studied about it.
Homeostatic organs are skin, liver, kidney lungs, endocrine glands etc.
Skin as homeostatic organ: Skin helps in temperature regulation. It possesses pigment cells (chromatophores and melanophores), sweat glands and sebaceous glands which help in controlling the heat and fluid balance. The melanin pigment helps to absorb solar heat and increase body temperature.
Kidney as homeostatic organ: Kidneys are the chief excretory and osmoregulatory organs. These also play key role in homeostasis. For example,
(a) Regulation of water content by ADH
(b) Regulation of salt or ion concentration in blood
(c) Maintain acid base balance in body (Lactic acid, ketones, sulphuric acid etc)
(d) Blood volume is regulated by the kidney

Liver as homeostatic organ: Liver is a key homeostatic organ due to the following reasons:
(a) Regulation of Carbohydrate, lipid and amino acid metabolism.
(b) Regulation of amount of glucose in blood by gluconeogenesis process.
(c) It maintains the optimum temperature
(d) Liver produces the bile. Bilirubin and Biliverdin, by products of dead RVC are excreted from the liver.

Lungs as homeostatic organ: It balances the concentration of O2 and Co2 in blood at the best level for the cells’ chemical reaction.