Control and Coordination

Control and coordination are provided by ____

Nervous and Muscular tissue

Receptors

All information from our environmentis detected by the specialised tip of nerve cells

Located : Sense organs

Gustatory receptors

Taste

Olfactory receptors

Nose

Nerve impulse

An electrical signal that passes along the neuron.

Structure of Neuron

Dendrite Tip:
The information acquired at the end of the dendrite tip of a nerve cell, sets off a chemical reaction that creates an electrical impulse,

Axon:
The impulse travels from the dendrite to the cell body and then along the axon to its end.

Nerve ending:
At the end of the axon, the electrical impulses releases some chemicals.

Synapse ( Neuromuscular junction) :
The chemicals cross the synapse And start a similar electrical impulse in a dendrite of the next neuron.

Sensory Neuron

Carry nerve impulse from receptors or sense organs to brain or spinal cord

Motor Neuron

Carry nerve impulse from Central nervous system ( brain and spinal cord ) to the effector organs like muscles or glands.

Relay Neuron

Connect Sensory to motor neuron. They are located in the brain and spinal cord.

How do nerveous impulses travel throughout the body?

1. All information from our environmentis detected by the receptors present in the body which transfer it to the sensory neuron.

2. The information is acquired at the end of the dendrite tip of a neuron causes a chemical reaction that produces an electrical impulse

3. This impulse travels from the dendrite of sensory neuron to its cell body ( cyton ) and then along the axon to its end

4. At the end of axon, the electrical impulse causes the release of some chemicals aka neurotransmitters

5. These chemicals cross the synapse and start a similar electrical impulse in dendrite of next neuron

6. A similar synapse allows the delivery of such impulses from neuron to other cells such as muscles cells or glands ( effectors )

Neuromuscular Junction

The point where muscle fiber comes in contact with a motor neuron carrying a nerve impulse from the Central Nervous system

AKA Synapse.

Limitations to the Use of Electrial Impulse

1. The electrical impulse will reach only those cells that are connected by a nervous tissue, not each and every cell in the body

   1. Once an electrical impulse is generated in a cell and transmitted the cell will take some time to reset its mechanism before it can generate and transmit a new impulse.

Reflex Action

Its is an automatic and rapid response to a stimulus, It protects the body from damage and does not invlove conscious thought.

Reflex actions are controlled by ___ and why not the brain.

Reflex actions are controlled by Spinal cord and not the brain as it takes more time to instruct the muscles too move.

Which neruron transports the reflex action?

It is passed straight to the Motor neuron through a relay neuron.

Spinal Cord

Nerves from all over the body meet in a form of a bundle on their way to the brain. Hence the process of detecting signals is quick.

Reflex arc

The pathway taken by the nerve impulses in a reflex action.

Stimulus / Danger→ Receptor ( Sense organs ) → Sensory neuron → Spinal Cord (Relay neuron) → Motor neuron → Effector (muscle)

Effector : Executes the effect by neuromuscular movement

Importance of reflex action

It enables an immediate response to an harmful stimulus.
It reduces the overloading of the brain
it increases the chances of survival

PNS ( Peripheral Nervous System )

It facilitated the communication between the Central Nervous system and other parts of the body.
Types: Cranial Nerves and Spinal Nerves

Cranial Nerves

Nerves which emerge from the brain and spread throughout the head

Spinal Nerves

Nerves which emerge from the Spinal Cord and spread through the body.

CNS

Central Nervous system : It is the centre of control and coordination of the body activities.
Types : Brain and Spinal Cord.
Recieves information from all parts of the body and integrates it.

Human Brain

The main coordinating centre of the body which enables organism to think and take decisions.

The human brain recieves information from the sense organs, inteprets it and sends instructions to the muscles or other organs.

Functions of the Human brain

1. It coordinates activites of the body so the mechanisms and hormonal reactions of the body work together.

2. It recieves the informations carrying nerve impules from all sensory organs of the body

3. It correlates the various stimulus from different sense organs and produces appropriate reaction

Forebrain

The forebrain is the Most Important part and the largest part of the brain.

It does all the main thinking. It recieves sensory impulse from various receptors in the body.

Cerebrum: It is responsible for the main thinking part of the brain. It is responsible for reasoning, speech, hearing and intelligent sights.

Sensory Areas : It recieves various sensory impulses from various receptors like ears and nose.

Association Areas: It recieves sensory information and inteprets it by relataing it to past experiances and other receptors

Hypothalamus : Controls the temperature, urge to eat and drinking.

Midbrain

It connects the forebarin to the hindbrain. It controls the head, neck and trunk movement. It controls the reflex movement of the eye muscles, pupil. To locate the sounds and visual reflex that involved in focusing of the objects.

Hindbrain.

Provides the connections between spinal cord and rest of the brain.

Cerebellum: It controls and coordinates different musculary actions.
Its is responsible for percision of voluntary actions.
It maintains posture and equilibrium of the body.

Medulla: Controls Involuntary actions such as breathing, blood preassure, salvation and vomitting.

Pons: It takes part in respiration. It relays impulses between different parts of the brain.

Protection of the Brain

The body is designed in such a way that the brain sits inside a bbony boc called cranium and contained in a fluid filled ballon which provides as an shock absorption.

Protection of the Spinal Cord

A hard bumpy structure called vertebral column or backbone present at the back protects the spinal cord

Immediate response to Stimulus

Plants use electrochemicals to convey information from cell too cell. Plants do not have specialised tissue for conduction of information

Plants cell change their shape by changing the amount of water. Shrinking or swelling.

Tropic Movement

Movement due to growth, these are directional movements in plants due to which the plants appears to move.

Phototropic Movement

Stimulus: Light
Movement of plant part in response to light.

Shoots : Towards lights
Roots : Away lights

Geotropic Movement

Stimulus: Gravity
Movement of plant part in response to Gravity

Shoots: Towards / Upwards Gravity
Roots: Away / Downwards Gravity

Hydrotropic Movement

Stimulus: Water
Movement of plant part in response to water.
Roots: Towards water

Chemotropic

Stimulus: Chemical
Movement of plant part in response to chemical.
Ex: Growth of pollen tube towards ovules during fertilisation

Hormones

A chemical compound, which diffuse all around the original cells and is detected by the other cells using special molecules.

Why chemical communications and not electrical impulse?

Cells cannot continously create and transmit electricaal impulses. Thus, most organism use chemical communications since it reaches all the cells.

Plant hormones : Auxins

Synthesised at the tip of the shoots.
Helps the cells grown longer.
They diffuses towards the shady side of the shoot simulating the cells.

Plant hormones : Gibberellins

Help in the growth of the stem and flowers

Plant hormones : Cytokinins

Promote Cell division.
Highest concentrations: Occur in seeds and flowers

Plant hormones : Abscisic Acid

Responsible for wilting of leaves.

Endocrine Glands

Other name: Ductless gland
Secrete hormone that act on distant sites known as Target organs or cells

Hypothalamus

Plays an important role in the release of many hormones.
Ex: When growth hormone is low, it releases growth hormone.
Controls urine, temperature and hormone production control.

Pituitary gland

Secretes: Growth hormone
Regulates overall growth and development.
The pituitary gland's main function is to produce and release hormones that regulate many bodily functions. It's often called the "master gland" because of this.

Pineal Gland

Secretes: Melatonin

Regulates: elevated levels at night (during dark hours) and low levels during the day (during light hours).

Function : to receive information about the daily light-dark (day-night) cycle from the retinas in your eyes

Adrenal Gland

Secretes: Adrenaline
Its secreted directly into the blood and carried to different parts of the body.

Involves preparation of fight and flight response.

It works in stress situations, it targets hearts, which makes it beat more.

Thyroid Gland

Secretes: Thyroxin
It helps in regulating carbohydrates, proteins, and fat metabolism.
Iodine is necessary for synthesis of thyroxine.

Parathyroid Gland

Secretes: parathyroid hormone (PTH)

Function: regulates the amount of calcium in the blood.

This hormone is essential for healthy bones, muscles, and nerves. 

Thymus

Function : to produce and mature T lymphocytes, a type of white blood cell that helps the body fight infection.

Location : in the chest, between the lungs, and in front of the heart. 

Testes Gland

Secrete: Testosterone
Changes associated with puberty and Development of Male Organs

Ovaries

Secretes: Oestrogen
Development of Female Sex organs and Regulates menstrual cycle.

Pancrease

Secretes: Insulin
Regulates blood sugar level

A - Pituitary
B - Thyroid
C -Adrenal
D - Pancreas
E - Ovary
F - Testis.

1. Cerebrum

2. Gray matter

3. White matter

4. Mid brain

5. Cerebellum

6. Spinal Cord

7. Medulla Oblongata

8. Hypothalamus

9. Pituitary body

A is the receptor,

B is sensory neuron

C is a Synapse

D is an effector muscle connected to a motor neuron.