CONTROL AND CO-ORDINATION

Contents at a glance

1. Structure and function of brain and spinal cord2. PNS and ANS3. Transmission of nerve impulse4. Reflex action 5. Sensory receptors; Eye and ear6. Endocrine glands and their hormones7. Hypothalamus8. Hormones as messengers and regulators

STRUCTURE AND FUNCTION OF BRAIN AND SPINAL CORD

• The brain and spinal cord constitute central nervous system CNS.

• CNS is derived form the embryonic ectoderm.• The brain and spinal cord are surrounded by

connective tissue membranes called meninges.• Its types are as follows

1. Dura mater 2. Arachnoid mater3. Pia mater

Types of MENINGS

Archanoid materIt is middle, thin, vascular,

membrane.

Pia materIt is a inner, thin,

vascular membrane.

Dura materIt is a outer, thick,

fibrous membrane.

HUMAN BRAIN • Human brain is well protected in bony box called

cranium • Weight - 1300 -1400 gms • Volume - 1300 -1500 c.c.• Develops full-six years; contains about 30,000 million

neurons• Human brain is divided into following types:

1. Forebrain 2. Midbrain 3. Hindbrain

BRAIN

Forebrain

Olfactory lobe Cerebrum Diencephalon

Midbrain

Corpora Crura cerebri

Hind brain

Cerebellum Pons varolii Medulla oblongata

HYPOTHALAMUS

1) It is a part of fore brain 2) It is made up of grey matter3) It is connected to the pituitary gland by means of a

stalk known as INFUNDIBULUM STALK 4) Function:

1) It regulates body temprature 2) It controls the secretion of

anterior lobe of pituitary gland.

SPINAL CORD(1) Medulla oblongata leaves the brain almost at a right

angle and further continue as a structure known as SPINAL CORD

(2) It is a long ,whitish colour rod present on the dorsal side of the body

(3) Externally it is protected by vertebral column (4) Externally it is covered by meninges(5) In adult it's length is about 45cm (6) The terminal part of the spinal cord is called hilum-

terminale(7) Function: It acts as a pathway of nerve-impulses

between the brain and the parts

T.S. OF SPINAL CORD

(1) Ependyma is surrounded by one type of nervous tissue called as GREY MATER

(2) Grey mater is of ‘H-shaped’(3) Grey mater shows 2 dorso lateral and 2 ventro lateral

projection called as dorsal horns and ventral horns.(4) Grey mater is surrounded by another type of nervous tissue

known as white mater . (5) White mater produces 3 columns :

a) Dorsal column b) Ventral column c) Lateral column

NERVOUS SYSTEM

Peripheral nervous system

(PNS)

Sensory nerve Motor nerve Mixed nerve

Autonomic nerve system

Sympathetic nerve system

Parasympathetic nerve system

Synapse:(1) It is a gap between axon of one neuron and dendron of other

neuron.(2) Two synapse are present :one in the axon of sensory neuron

and dendron of adjuster neuron second synapse is present between axon of adjuster neuron and dendron of motor neuron.

TRANSMISSION OF IMPULSES THROUGH SYNAPSE

REFLEX ACTIONi. Definition: The automatic sudden and rapid respons to the stimulus is

called reflex action .ii. Eg: closing of eye at the approach of any object towards .iii. Significance: It give quick response, it protects the body from danger. iv. Mechamism of reflex action:

a) Receptor Organ: (1) It is part of the body which receives the stimulus and converts

is into the nerve impulse . (2) Sensory neuron: It is the neuron which carry the nerve impulse

from the receptor organ tothespin the receptor organ to the spinal cord .

(3) Adjustor neuron: lt connects sensory neuron to the motor neuron.

(4) Motor nerve: carries the nerve impulse from the spinal cord to the effector organ .

(5) Effector organ :It is a part of a body which receives the nerve impulse and show the response.

EYES

1. A pair of eyes are located in sockets.2. It is formed by three layers. A) Outer (sclera) B) Middle (cornea) C) Inner (choroid)Eyes consist following parts:-3. Retina4. Crystalline lens5. Optic nerve 6. Ciliary body (membrane)

EARS

1. The ear carry out two important sensory function2. Hearing and maintenance of body Equilibrium3. The ear is composed of three division a) Outer ear - Collects the sound. b) Middle ear - Transmission of

sound from external auditory

to internal ear. c) Internal ear - Hair cells act as auditory receptors .

PITUITARY GLAND

1. Pituitary gland are also known as master gland .2. It is under control of hypothalamus.3. They are mostly water soluble and some are fat

soluble .MORPHOLOGY OF PITUITARY GIAND4. Size – 1.5x10x6 mm5. Shape – Pea shape 6. Weight – 0.5 to 0.6 gm

Morphology of Pituitary Gland

Anterior lobe

Pars turberalis

Pars distalis

Pars intermedia

Posterior lobe

Median eminence Infundibulum Pars nervosa

1

•Pineal body

2

•Pituitary gland

3

•Thyroid gland

4

•Parathyroid gland

5

•Thymus gland

6

•Adrenal gland

7

•Pancreatic islet

8

•Ovaries in female

9

•Testis in male

Hormones of Pituitary Gland

Hormones of Pars Distalis

Somatotrophic Hormone

Thyroid Stimulating Hormone

Triiodothyronine Tetraiodothyronine

Adreno Cortico Tropic Hormone Prolactin Gonado Tropic

Hormones

Follicle Stimulating Hormone

Luetinizing Hormone

Hormones of Neurohypophysis

Anti Diuretic Hormone Oxytocin Coherin

TSH

Adenohypophysis

TSH

Thyroid follicle

Thyroxine

Adenohypophysis

FSH

Follicle cell of ovary

Estrogen

FSH

ACTH

Adenohypophysis

ACTH

Cortex of adrenal gland

corticosteriods

Adenohypophysis

ICSH

Interstitial cell of testis

Testosteriods

ICSH

LTH

Adenohypophysis

LTH

Mammary gland

Milk