Reflex action, Biology

Assignment Help:

REFLEX ACTION -

  • Marshel Hall discovered reflex action. Best & Taylor defined it. Reflex action is functional unit of CNS.
  • It is sudden, immediate involuntary action against external stimuli. In man it is poly-synaptic.
  • If we prick needle on skin, somatic sensory nerves bring impulses to grey matter. Here these are analysed & order is given to muscle by motor nerve.
  • The path from which impulse is passed is reflex arch.
  • Minimum time is consumed in it. It is not under control of brain.

Some common reflex actions are -

1. Coughing

2. Yawning

3. Sneezing

4. Knee-jerk reflex

5. Bleenking of eyes

6. Scratch reflex

EXAMPLE -

1.       Cycling.

2.       Watering of mouth.

3.       Blinking of eyes in sharp light.

4.       Withdrawal of leg in pithed frog.

5.       Flow of bile from gall bladder.

6.       Peristalasis.

7.       Heart beat.

2243_reflex action.png

SIGNIFICANCE -

1. It enables animal to respond immediately to the harmful stimuli so that no harm is caused to it.

2. It gives more time to brain to work.


Related Discussions:- Reflex action

Explain major limiting factors of photosynthesis, Q. What are the three maj...

Q. What are the three major limiting factors of photosynthesis? The three major limiting factors of photosynthesis process are light intensity, carbon dioxide temperature and c

What is meant by vaso-dilation, a) What is meant by 'vaso-dilation'? ...

a) What is meant by 'vaso-dilation'? b) What are the effects of vaso-dilation in the skin?   (a) Vaso-dilation is an enhance in diameter of small arterioles and

Homestasis, why does an organism internal environment change

why does an organism internal environment change

What is resting membrane potential of a neuron, What is resting membrane po...

What is resting membrane potential of a neuron? What is the function of sodium potassium pumps in maintaining it?

Accuracy of stress echocardiography, Q. Define Accuracy of Stress Echocardi...

Q. Define Accuracy of Stress Echocardiography? The accuracy of stress echo tests for the detection of coronary artery disease is expressed as the sensitivity and specificity of

Nucleus of a spermatogonia, Plot the amount of DNA in the nucleus of a sper...

Plot the amount of DNA in the nucleus of a spermatogonia from the G1 stage prior to the first meiotic division through the completion of meiosis. Label each of the major stages of

Define methods for estimation of iron and haemoglobin, Define Methods for E...

Define Methods for Estimation of Iron and Haemoglobin? In this section we shall study the procedure involved in estimation of iron in any sample first followed by a review on t

Seed structure, why mung beans has no endosperm while castor bean and maize...

why mung beans has no endosperm while castor bean and maize seed has?

Explain crossing over in genetics, Explain Crossing Over in genetics? C...

Explain Crossing Over in genetics? Crossing over is when the arms of homologous chromosomes exchange segments (and therefore genes) with each other. Recall that one of the homo

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd