CELLS

Presentation byMedha Pandey

List of the cellsAdipocytesa. White adipocytesb. Brown adipocytesChondroblastsNeuronsAmeloblasts

AdipocytesFat storing cellsAlso known as lipocytes, fat cells

Typesa) White adipocytesb) Brown adipocytes

White adipocytes Are monovacuolar or unilocular Major type of adipocytes Accounts for 20% of total body weight in men and

25% in women

MORPHOLOGY OF WHITE ADIPOCYTE

1. Oval or spherical in shape2. 25 to 200 microns3. Contains a large lipid droplet4. Cytoplasm pushed to periphery5. Signet ring like appearance

FUNCTION OF WHITE ADIPOCYTES1. Insulation2. Mechanical cushion3. Source of energy

LOCATION1. Under the skin: subcutaneous fat

2. Surrounding the vital organs: visceral fat

3. Inside bones: bone marrow

BROWN ADIPOCYTESAre multivacuolar or multilocularContain many lipid droplets

LOCATION

1. Abundant in infants2. Upper chest and neck of adults

MORPHOLOGY1. Shape may be oval or polygonal2. Size: 60 microns3. Has considerable amount of

cytoplasm4. Scattered lipid droplets5. Densely packed mitochondria

FUNCTION1. Heat generation2. Burns calories

CHONROBLASTSCells present in the cartilageFound at the end of bones, tips of nose, external

ears, epiglottis and joints (intervertebral) discs of knee

MORPHOLOGY OF CHONDRBLASTS

Cells embedded in lacunaeAre about 4 microns in size

FUNCTION Matrix and other ground substance secretion

Chondrocytes embedded in matrix

NEURONS

neuronsThe term neuron was coined by the German

anatomist Heinrich Wilhelm WaldeyerAlso known as nerve cellsAre electrically excitableCore components of the nervous system,

which includes the brain, spinal cord, and peripheral ganglia

LOCATION1. Axons reach everywhere2. Cell bodies are concentrated on the Central

Nervous System.

Types of neurons

On the basis of function2 TYPES:

1. Sensory neuron2. Motor neuron

Sensory neuronsAlso known as afferent neuronsRespond to sound, light, touch and numerous other

sensory stimulusSend the signal received by sensory organs to spinal

cord or brain

Motor neuronsAlso known as efferent neuronsCause muscle contraction and affect glandsReceive signal from brain and spinal cord

MORPHOLOGY OF THE NEURONS

A Cell Body: contains a nucleus, endoplastic reticulum, mitochondria and other organelles

The Dendrites: are small branches bringing information to the cell body.

The Axon: nerve fiber, is the longest fiber

of the neuron which takes information away from the cell body to the connecting neuron.

Shape and size4 microns (.004 mm) to 100 microns (.1 mm) in

diameter. Their length varies from a fraction of an inch to

several feet.

FUNCTION

allow an organism to sense an stimuli either in external or internal environment

analyze and integrate the stimuli to provide appropriate, coordinated responses in various

organs

conduct nerve impulses from the sense organs and receptors to the central nervous system

 

Transmit the impulse from CNS to an effector organ so as to react to the stimulus

supply the connection between the afferent and efferent neurons as well as different parts of the central nervous system

AmeloblastsCells in teeth root, are present only during tooth

development

MORPHOLOGY OF AMELOBLAST SIZE: 4 microns in diameter, 40 microns in

lengthLong with hexagonal cross sectionHas a secretory end: Tome’s process which

is a hexagonal pyramid like structureThese cells become functional only after

dentine has been formed by odontoblasts

Functionsecrete the enamel

proteins enamelin and amelogenin

mineralization to form enamel on teeth

LOCATION1. Located on the root of the teeth.

A slide preparation of Ameloblasts showing Tome’s process

REFERENCEShttp://i-need-more.com/amelogenesis-1/

(6 April 2012)http://ajpcell.physiology.org/content/299/6/

C1299/F1.expansion (7 April 2012)http://www.bcb.uwc.ac.za/sci_ed/grade10/

mammal/nervous.htm (9 April 2012)http://www.sportsci.org/encyc/adipose/

adipose.html (9 April 2012)http://www.diabesity.eu/adipocyte.htm (11

April 2012)http://wdict.net/gallery/ameloblast/ (13 April

2012)

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