Posts filed under: ‘Anatomy‘




Urinary system

bladder – hollow organ that stores urine until excreted.
kidney – 2bean-shaped organs that take waste from blood & produce urine.
ureter – 2tubes, each of which carries urine from a kidney to the bladder.
urethra – tube that carries urine from bladder out of body.

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Add a comment October 8, 2007

Eye

Cornea – clear, dome-shaped tissue covering  front of eye.
Iris – colored part of eye, ctrls amount of light that enters eye by changing pupil size.
Lens – crystalline structure located just behind iris, focuses light onto retina.
Optic nerve – transmits electrical impulses from retina to brain.Pupil – opening in center of iris, changes size as the amount of light changes. More the light,  smaller the hole.
Retina – sensory tissue that lines back of eye, contains millions of photoreceptors (rods & cones) that convert light rays into electrical impulses that are relayed to brain via optic nerve

Vitreous humor – a thick, transparent liquid that fills  center of eye. It is mostly water, gives the eye its form & shape.

Eyebrows r dense patches of hair above eyes.

Eyelashes r long hairs on edges of eyelids.

Eyelids are flaps of skin that cover & protect eyes

Add a comment October 8, 2007

Ear

Sound is collected by pinna/auricle (the visible part of ear), directed through outer ear canal(tube). Sound makes eardrum/tympanic membrane, which is a thin membrane, vibrate, which in turn vibrates 3tiny bones in middle ear. They r hammer/malleus, anvil/incus, u shaped stapes. Cochlea in inner ear is snail-shaped. 3loops of fluid filled tubes called semi circular canals attached to cochlea hep us maintain our sense of balance. Nerves carry electro chemical signals from cochlea to brain. Middle ear is connected to back of nose. It equalises pressure betn middle ear & air outside. when u “pop” ur ears as u change altitude, u’re equalising the air pressure in ur middle ear. On average, people can hear sounds in the freq’s betn 20-20,000Hz.  

Add a comment October 8, 2007

Spinal system

3 main parts of Brain: cerebrum, cerebellum, brain stem (medulla).  

Cerebellum – the part of the brain below the back of the cerebrum. It regulates balance, posture, movement, and muscle coordination.
Corpus Callosum – a large bundle of nerve fibers that connect the left and right cerebral hemispheres. In the lateral section, it looks a bit like a “C” on its side.
Frontal Lobe of the Cerebrum – the top, front regions of each of the cerebral hemispheres. They are used for reasoning, emotions, judgment, and voluntary movement.
Medulla Oblongata – the lowest section of the brainstem (at the top end of the spinal cord); it controls automatic functions including heartbeat, breathing, etc.
Occipital Lobe of the Cerebrum – the region at the back of each cerebral hemisphere that contains the centers of vision and reading ability (located at the back of the head).
Parietal Lobe of the Cerebrum – the middle lobe of each cerebral hemisphere between the frontal and occipital lobes; it contains important sensory centers (located at the upper rear of the head).

Temporal Lobe of the Cerebrum – the region at the lower side of each cerebral hemisphere; contains centers of hearing and memory (located at the sides of the head).
Pituitary Gland – a gland attached to the base of the brain (located between the Pons and the Corpus Callosum) that secretes hormones.
Pons – the part of the brainstem that joins the hemispheres of the cerebellum and connects the cerebrum with the cerebellum. It is located just above the Medulla Oblongata.
Spinal Cord – a thick bundle of nerve fibers that runs from the base of the brain to the hip area, running through the spine (vertebrae).
Function: Human brain is a complex organ that allows us to think, move, feel, see, hear, taste, smell. It ctrls our body, receives info, analyzes info, stores info (our memories). Brain produces electrical signals, which, together with chemical reactions, let the parts of the body communicate. Nerves send these signals throughout the body. Size: consists of gray matter (40%), white matter (60%) within the skull. Brain cells include neurons, glial cells.

Nourishment of the brain: Although the brain is only 2% of the body’s wgt, it uses 20% of the oxygen supply & gets 20% of the blood flow. Blood vessels (arteries, capillaries, veins) supply the brain with oxygen & nourishment, & take away wastes. If brain cells do not get oxygen for 3-5mts, they begin to die. Cerebrospinal fluid (CSF) surrounds the brain.

The nervous system: The cranium (top of the skull) surrounds & protects the brain. Spinal cord is surrounded by vertebrae (hollow spinal bones). Also, some muscles serve to pad & support the spine. More subtly, the blood-brain barrier protects the brain from chemical intrusion from the rest of the body. Blood flowing into the brain is filtered so that many harmful chemicals cannot enter the brain.

7 cervical vertebrae – located in the neck, below the skull. A vertebra is one of the series of small, connected bones in the spine that surround & protect the spinal cord. The plural of vertebra is vertebrae.
coccyx – 4 fused vertebrae located below the sacrum.
5 lumbar vertebrae – located below thoracic vertebra.
sacrum – 5 fused vertebrae located below the lumbar region.
skull – the bones in the head that protect the brain.
12 thoracic vertebrae – 12 vertebrae in the mid-back.

Add a comment October 8, 2007

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