Sathi khan dool

25/05/2026

نبي پاڪ کي نام کا جانور

21/05/2026

Topics You Need More Practice In — Easy Explanation

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1. Nervous System Terms

The nervous system controls and coordinates body activities.

Main Terms

Neuron

A neuron is the basic unit of nervous system.

It carries messages called nerve impulses.

Parts of Neuron

Dendrites

Receive messages.

Carry impulses toward cell body.

Cell Body

Contains nucleus.

Controls activities of neuron.

Axon

Carries impulses away from cell body.

Myelin Sheath

Fatty covering around axon.

Speeds up nerve impulses.

Synapse

Tiny gap between two neurons.

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Important Trick

Dendrite → “D” = Directs impulses toward body

Axon → Away from body

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2. Synapse and Neuron Structure

Synapse

The gap between two neurons where messages pass chemically.

Function

Helps transfer nerve impulse from one neuron to another.

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Simple Flow of Impulse

Dendrite → Cell body → Axon → Synapse → Next neuron

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3. Reflex Action

A reflex action is:

> A quick automatic response to a stimulus.

Example

Touching a hot object and quickly removing hand.

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Reflex Arc Pathway

Stimulus → Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector

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Important Point

Reflex action is mainly controlled by:

Spinal cord instead of brain for quick response.

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4. Breathing Mechanism

Breathing has two steps:

A. Inhalation (Breathing In)

What Happens?

Diaphragm contracts.

Becomes flat.

Chest cavity becomes larger.

Air enters lungs.

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B. Exhalation (Breathing Out)

What Happens?

Diaphragm relaxes.

Becomes dome-shaped.

Chest cavity becomes smaller.

Air leaves lungs.

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Easy Trick

IN-halation = Air goes IN

EX-halation = Air goes EXit

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5. Homeostasis Concepts

Definition

Homeostasis means:

> Maintaining stable internal conditions in the body.

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Examples of Homeostasis

Temperature Control

Sweating cools body.

Shivering warms body.

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Water Balance

Kidneys control amount of water in body.

ADH Hormone

ADH increases water reabsorption in kidneys.

More ADH → More water saved.

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Blood Glucose Control

Insulin

Lowers blood glucose.

Glucagon

Raises blood glucose.

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Important MDCAT Points

Topic Important Point

Synapse Gap between neurons
Axon Carries impulses away
Dendrite Carries impulses toward
Reflex action Controlled by spinal cord
Inhalation Diaphragm flat
Exhalation Diaphragm dome-shaped
ADH Water reabsorption
Myelin sheath Speeds impulses

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Quick Memory Tricks

Synapse = “Signal jump place”

Myelin sheath = “Speed cover”

Reflex = “Rapid automatic response”

Homeostasis = “Body balance”

18/05/2026

جاميعه راشديه قادريه با۽ پاس روڊ ٺل
زير تعمير مسجد رحمت اللعالمين

16/05/2026

22/04/2026

With Sajid Shahid – I just earned their Fan of the year badge! 🎉