Spinal cord

SPINAL CORD -
The spinal cord is the part of CNS which is contained within the vertebral canal & is the prolongation of the brain.It  is surrounded by a clear fluid called Cerebral Spinal Fluid (CSF), that acts as a cushion to protect the delicate nerve tissues against damage from banging against the inside of the vertebrae.

The anatomy of the spinal cord itself, consists of millions of nerve fibres which transmit electrical information to and from the limbs, trunk and organs of the body, back to and from the brain. The nerves which exit the spinal cord in the upper section, the neck, control breathing and the arms. The nerves which exit the spinal cord in the mid and lower section of the back, control the trunk and legs, as well as bladder, bowel and sexual function.
The brain and spinal cord are referred to as the Central Nervous System, whilst the nerves connecting the spinal cord to the body are referred to as the Peripheral Nervous System.
It develops from that portion of neural tube which lies caudal to the level of the 4th pair of somites.

It is about 45 cm (18'') long & about 1.25 cm (1/2'') wide.

 
Extention:
                      From the horizontal plane passing between the middle of the odontoid  process of the 2nd cervical vertebrata & terminates below in a conical extremity , the conus medullaris at the lower border of the body of 1st lumber vertebra.

Enlargements:
                                It present two enlargements -  Cervical & Lumber. The cervical enlargement extends  from the level of 3rd cervical to the 2nd thoracic segment of the spinal cord. From this enlargement nerves for the upper extremities emerge out.
The lumbar enlargement extends from the ninth thoracic vertebra to the twelfth thoracic vertebra. From it nerves for lower extremities emerge out.


Filum terminale :
                                   A delicate, thread like non-nervous filament, about 20 cms long. Extends from the lower end of conus medullaries and terminates by being attached to the dorsal aspect of first coccygeal vertebra.

Coverings :
                        It has three covering , from without in-words-dura mater, arachnoid & pia mater is subarachnoid space which contain CSF and extends as down as the 2nd sacral vertebra.

Parts of Spinal cord :
Onbcross section, the spinal cord has two parts-
1) Central _ grey mater :It is composed of a mass of nerve cells, nerve fibers consisting of both  
    axons & dendrons together  witha framework of neuroglial cells.It is divided into two symetrical
    halves which are connected by a transverse band , resemble the letter H. It has three column
    (horn) -
    a) Anterior horn.
    b)Lateral horn (only in thoracic horn) &
    c)Posterior horn.
2) Peripheral - white matter : It surrounds the grey matter and consists of nerve fibres & neuroglia. It appear as white because most of the fibre are myelinated.
3) Central canal : It exists through out the spinal cord and is continuous above with the inferior angle of 4th ventiricle and below it expands as far down as 2'' within filum terminale.

Function of Spinal cord :

   1) It is the main pathway for all incoming and outgoing impulses from the higher center to the
       periphery & vice versa.
  2) It is the main center of reflex actives.
  3) It exerts tropic control over the muscular system.

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Structure of eye

The eye is a very complex organ that sends a huge amount of information to the brain. It has a very specific design to capture and analyze light. In its simplest description, the eye is a box, with a lens to focus the light that enters it, and cells to process the light.It is a window to our emotions, and some say, to the soul. Explore the complexities of the human eye.

                                                         fig. Structural of human eye.

Optic nerve :
                 This carries the impulses generated by the retina to the brain to be turned into images in the   brain.

Retina :
          This is a membrane layer in the inside of the eye that contains rod cells (lets you see in the dark
          because they are sensitive to low light intensities) and cone cells (lets you see in bright light because its
          works best at higher light intensities).
          It converts the light into electric impulses to be sent to the brain via the optic nerve. This conversion is  
          called photoelectric conversion.

pupil : The pupil is actually the gap created by the iris.
           The pupil either dilates or contracts with the help of the iris.
           This controls the amount of light entering the eye so that the retina and lens doesn't get damaged.
           In bright light the pupil becomes small by relaxing the muscles in the iris in dim light it dilates (becomes
          big) by contracting the muscles in the iris.

Iris :    This is the muscle surrounding the pupil gap.This helps in dilating and making the pupil smaller.
           Its made up of radial and radial muscles (antagonistic pairs).The longitudinal muscles contract and the
           radial muscles relax to make the pupil big. The vise verse  happens to make the pupil smaller.
cornea :This is the transparent layer of the sclera, which is also thinner than the sclera, that covers the front    
             part of the eye (that is the iris, pupil, and anterior chamber of the eye).
             It has 2 functions. Its most important functions is to help in the double refraction of light tot he retina    
             with the help of the lens.
             The light first gets refracted by the cornea then this light travels to the lens to get refracted further      
            thereby bringing about vision. The other function is for it to act as a protection layer.

lens  :  This is an transparent organ in the inner eye that is filled with a liquid. It helps the refraction of light,
           with the help of the cornea, onto the retina.
           The lens helps in seeing far and near objects be contracting and relaxing with the help of the ciliary
            bodies (muscles) that are connected to them.
           The ciliary muscles contract to make the lens thin and help see distance objects by refracting the light
           accordingly on the retina.
           The ciliary bodies relax to make the lens fatten up to see near objects by refracting the light
           accordingly on the retina.
         When this method of lens contraction and relaxation malfunctions you get either short sightedness or
          near sightedness.
Ciliary body  :
                      Part of the eye between the iris and the choroid.
                   
                 

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Human ear

The ear is the organ that detects sound.
It not only receives sound, but also aids in balance and body position.
The ear is part of the auditory system.
It has external, middle, and inner portions.
The outer ear is called the pinna and is made of ridged cartilage covered by skin.
Sound funnels through the pinna into the external auditory canal, a short tube
 that ends at the eardrum (tympanic membrane).

Human Ear:
The human ear has three main sections, which consist of the outer ear, the middle ear, and the inner ear.
Sound waves enter your outer ear and travel through your ear canal to the middle ear.
The ear canal channels the waves to your eardrum, a thin, sensitive membrane stretched tightly over the entrance to your middle ear.
The waves cause your eardrum to vibrate.

The human ear can respond to minute pressure variations in the air if they     are in the audible frequency range, roughly 20 Hz - 20 kHz.
It is capable of detecting pressure variations of less than one billionth of atmospheric pressure.
The threshold of hearing corresponds to air vibrations on the order of a tenth of an atomic diameter.
This incredible sensitivity is enhanced by an effective amplification of the sound signal by the outer and middle ear structures.
Contributing to the wide dynamic range of human hearing are protective mechanisms that reduce the ear's response to very loud sounds.
Sound intensities over this wide range are usually expressed in decibels.

It passes these vibrations on to the hammer, one of three tiny bones in your ear.
The hammer vibrating causes the anvil, the small bone touching the hammer, to vibrate. The anvil passes these vibrations to the stirrup, another small bone which touches the anvil.
From the stirrup, the vibrations pass into the inner ear.
The stirrup touches a liquid filled sack and the vibrations travel into the cochlea, which is shaped like a shell.
Inside the cochlea, there are hundreds of special cells attached to nerve fibers, which can transmit information to the brain. The brain processes the information from the ear and lets us distinguish between different types of sounds.


The human ear can perceive frequencies from 16 cycles per second, which is a very deep bass, to 28,000 cycles per second, which is a very high pitch.
Bats and dolphins can detect frequencies higher than 100,000 cycles per second.
The human ear can detect pitch changes as small as 3 hundredths of one percent of the original frequency in some frequency ranges.
Some people have "perfect pitch", which is the ability to map a tone precisely on the musical scale without reference to an external standard.
It is estimated that less than one in ten thousand people have perfect pitch, but speakers of tonal languages like Vietnamese and Mandarin show remarkably precise absolute pitch in reading out lists of words because pitch is an essential feature in conveying
the meaning of words in tone languages.
The Eguchi Method teaches perfect pitch to children starting before they are 4 years old. After age 7, the ability to recognize notes does not improve much.

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Blood types

                                    Blood is a specialized fluid connective tissue in which there is liquid intercellular substance (plasma) and formed elements - (RBC,WBC and platelets ) suspended in the plasma which circulates in closed system of blood vessels. It is red , thick and slightly alkaline.
                     Blood is circulated around the body through blood vessels by the pumping action of the heart.
In animals with lungs, arterial blood carries oxygen from inhaled air to the tissues of the body, and venous blood carries carbon dioxide, a waste product of metabolism produced by cells, from the tissues to the lungs to be exhaled.

Blood is composed of -

                   A. Cellular substances:  45% (42%-45%)

                                                        1)  Erythrocytes or red blood corpuscles (RBC) 

                                                        2)  Leukocytes or white blood corpuscles (WBC)

                                                        3)  Platelets or thrombocytes. 

                   B. Liquid intercellular substance : i.e. plasma -55%(55%-58%) -

                                                                    Plasma contains -

1) Liquid( 91-92%)- water

2) Solid :(8-9%)

Blood 

Properties of Blood 

1) Blood volume : 5-6 liters

2) Normal reaction : Slightly alkaline , pH =7.36-7.45

3) Specific gravity : 1.052- 1.060

4) Viscosity : 4.5 times more viscus than water. 

5) Temperature : 36-38'c

6) Osmotic pressure : Average 25 mm of Hg .

7) Colour    : Red , due to presence of hemoglobin inside RBC.

8) Taste : Salty. 

Blood cell 

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Vitamins essential

Vitamin:

Vitamin means vital amine . Vitamin may be defined as a protent organic compounds which is found in food in variable  and minute quantity and must supplied to the animal organism from external sources, so that specific physiological function vital to life may go on normally .

*Vitamins * 

Depending upon their solubility in water , fat  and oils as well as fat solvent vitamins are divided into (two) 2 groups : 

• Fat soluble vitamins : Those present in fats and soluble in fat solvents ; Example: A,D,E & K .

• Water soluble vitamins : These are water soluble and includes vitamin B- complex   and vitamin C. It does   not stored in the body more than 48-72 hours except B12.

        Amount of daily required vitamins:
Vitamin A                                    - 5000 IU
Vitamin D                                     - 400 IU
Vitamin E                                      -15    IU
Vitamin K                                     -70    micro gm
Thiamine (B1)                                - 1.5   mg
Riboflavin (B2)                               -1.8   mg
Pantothenic acid (B)                      -   Unknown
Niacin                                           -20    mg
Folic acid                                      - 0.4  mg
Pyridoxine (B6)                             -2       mg
Vit.B12    3 micro mg
Vit. C or Ascorbic acid                 - 45 mg.

Different types of vitamins:

Vitamin A (Retinol and beta-carotene) 

 Vitamin B-complex 

 Vitamin B1 (Thiamine) 

 Vitamin B2 (Riboflavin) 

 Vitamin B3 (Nicotinic acid / nicotinamide) 

 Vitamin B5 (Pantothenic acid) 

 Vitamin B6 (Pyridoxine) 

 Vitamin B11 (Folic acid) 

 Vitamin B12 (Cobalamin) 

 Vitamin C (L-Ascorbic acid) 

 Vitamin D (Cholecalciferol / Ergocalciferol) 

 Vitamin E (Tocopherol) 

 Vitamin H (Biotin) 

 Vitamin K (Phylloquinone)

Essential food for vitamin supply 

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Eye anatomy

The human eye is the organ which gives us the sense of sight, allowing us to observe and learn more about the surrounding world than we do with any of the other four senses.  We use our eyesreading, working,  writing a letter, driving a car,watching televisionand in countless other ways.The eye is a slightly asymmetrical globe, about an inch in diameter. The front part of the eye (the part you see in the mirror) includes:
1.The iris.
2.The cornea.
3.The pupil.
4.The sclera.
5.The conjunctiva.

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Cardiovascular system

Cardiovascular System: 

The cardiovascular system includes the heart and the blood vessels. 

The heart pumps blood, and the blood vessels channel and deliver it throughout the body.

 Arteries carry blood filled with nutrients away from the heart to all parts of the body.

 The blood is sometimes compared to a river, but the arteries are more like a river in reverse.

 Arteries are thick-walled tubes with a circular covering of yellow, elastic fibers, which contain a filling of muscle that absorbs the tremendous pressure wave of a heartbeat and slows the blood down.

This pressure can be felt in the arm and wrist - it is the pulse.

 Eventually arteries divide into smaller arterioles and then into even smaller capillaries, the smallest of all blood vessels. One arteriole can serve a hundred capillaries.

 Here, in every tissue of every organ, blood's work is done when it gives up what the cells need and takes away the waste products that they don't need. Now the river comparison really does apply.

 Capillaries join together to form small veins, which flow into larger main veins, and these deliver deoxygenated blood back to the heart.

 Veins, unlike arteries, have thin, slack walls, because the blood has lost the pressure which forced it out of the heart, so the dark, reddish-blue blood which flows through the veins on its way to the lungs oozes along very slowly on its way to be reoxygenated.

 Back at the heart, the veins enter a special vessel, called the pulmonary arteries, into the wall at right side of the heart. It flows along the pulmonary arteries to the lungs to collect oxygen, then back to the heart's left side to begin its journey around the body again.

The heart has four chambers that are enclosed by thick, muscular walls.

 It lies between the lungs and just to the left of the middle of the chest cavity. The bottom part of the heart is divided into two chambers called the right and left ventricles, which pump blood out of the heart.

 A wall called the interventricular septum divides the ventricles.

                              The upper part of the heart is made up of the other two chambers of the    heart, called the right and left atria.

 The right and left atria receive the blood entering the heart. A wall called the inter atrial  septum divides the atria, and they're separated from the ventricles by the atrioventricular  valves. The tricuspid valve separates the right atrium from the right ventricle, and the mitral  valve separates the left atrium and the left ventricle.

            Two other heart valves separate the ventricles and the large blood vessels that carry blood leaving the heart. These valves are called the pulmonic valve, which separates the right ventricle from the pulmonary artery leading to the lungs, and the aortic valve, which separates the left ventricle from the aorta, the body's largest blood vessel.

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Anatomy of the Shoulder

The two main bones of the shoulder are the humerus and the scapula (shoulder blade).

The joint cavity is cushioned by articular cartilage covering the head of the humerus and face of the glenoid. The scapula extends up and around the shoulder joint at the rear to form a roof called the acromion, and around the shoulder joint at the front to form the coracoid process. Ligaments connect the bones of the shoulder, and tendons join the bones to surrounding muscles. The bicepstendon attaches the biceps muscle to the shoulder and helps to stabilize the joint.The end of the scapula, called the glenoid, meets the head of the humerus to form a glenohumeral cavity that acts as a flexible ball-and-socket joint.The joint is stabilized by a ring of fibrous cartilage surrounding the glenoid called the labrum.

Ligaments connect the bones of the shoulder, and tendons join the bones to surrounding muscles. The biceps tendon attaches the biceps muscle to the shoulder and helps to stabilize the joint.The end of the scapula, called the glenoid, meets the head of the humerus to form a glenohumeral cavity that acts as a flexible ball-and-socket joint.The joint is stabilized by a ring of fibrous cartilage surrounding the glenoid called the labrum.

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Human anatomy nose

The visible part of the human nose is the protruding part of the face that bears the nostrils.
 The shape of the nose is determined by the ethmoid bone and the nasal septum,
which consists mostly of cartilage and which separates the nostrils.
 On average the nose of a male is larger than that of a female.
The nasal root is the top of the nose, forming an indentation at the suture where the nasal bones meet the frontal bon.

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Respiratory system

The respiratory system is the anatomical system of an organism that introduces respiratory gases to the interior and performs gas exchange.

 In humans and other mammals, the anatomical features of the respiratory system include airways, lungs, and the respiratory muscles.

 Molecules of oxygen and carbon dioxide are passively exchanged, by diffusion, between the gaseous external environment and the blood.

Other animals, such as insects, have respiratory systems with very simple anatomical features, and in amphibians even the skin plays a vital role in gas exchange.

 Plants also have respiratory systems but the directionality of gas exchange can be opposite to that in animals.

The respiratory system in plants also includes anatomical features such as holes on the undersides of leaves known as stomata.

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The human brain is the center of the human nervous system.

The human brain is the center of the human nervous system.

It has the same structure as the brains of other mammals,

but is larger than expected on the basis of body size among other primates.

Estimates for the number of neuronsin the human brain range from 80 to 120 billion.

Most of the expansion comes from the cerebral cortex.

Fig: CNS

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Human anatomy

The human brain is the center of the human nervous system.

It has the same structure as the brains of other mammals,

but is larger than expected on the basis of body size among other primates.

Estimates for the number of neuronsin the human brain range from 80 to 120 billion.

Most of the expansion comes from the cerebral cortex, especially the frontal lobes,

which are associated with executive functions such as self-control, planning, reasoning, and abstract thought.

The portion of the cerebral cortex devoted to vision is also greatly enlarged in human beings,

and several cortical areas play specific roles in language,

a skill that is unique to humans.

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