Control and Coordination-2 Flashcards
Define reflex action
it refers to the simplest form of response in the human nervous system. It is spontaneous, automatic and mechanical in nature. It is a response to a stimulus acting on a specific receptor without consious effort and thought.
give the characteristics of a reflex arc
i)It is a rapid, simple and automatic response to a stimulus that is not under the voluntary control of brain
ii)It is an involuntary action.
iii) It takes very less time, about a few milliseconds, to give the response.
iv) It is controlled by the brain.
what are the types of reflex actions
->natural
natural reflexes are those for which no previous experience or learning is required
-> conditioned
conditioned reflexes are those for which develop during lifetime with experience and learning.
differetiate between natural and conditioned reflex actions
Natural:
i)No previous learning or experience is required.
ii) It is inherited from parents and hence is known as natural and unconditioned.
iii) Ex: Coughing, Sneezing
Conditioned:
i) Develops through experience or prior learning
ii) it is not transmitted through heredity.
iii) EX: Applying breaks when bicycling.
define reflex arc
The path that the nervous impulse takes during a reflex action is called reflex arc. It is a neural pathway that begins with the sensory organ at the receptor( ex: pain receptor at fingertip) and ends with motor neuron at an effector( muscle or gland).
what isthe path of reflex arc?
Stimulus
↓
Receptor
↓
Sesnroy enuron
↓
interneuron
↓
motor neuron
↓
effector
↓
response
what is the advantage of reflex actions
- this enables body to give quick response to harmful stimuli this protecting the body
-minimises the overload;/work burden of the brain
-in many animals, reflex arcs have evolved as efficient ways of functioning in the absence of true thought processes.
what is the spinal cord? Whats its functions?
i) Spinal cord is a bundle of nerves, protected by the vertebral column, that is a continuation of the medulla.
ii) Its functions are:
a) it plays an important role in reflex actions
b) It helps in the conduction of impulses from different parts of the body to brain and vice versa via electric impulses
what are parts of the brain
The brain has three such major parts or regions, namely the fore-brain,
mid-brain and hind-brain.
The fore brain consists of te cerebrun, thalamus, hypothalamus and pituitary gland.
The hind brain consists of the pons, medulla oblongata, cerebellum.
what is the forebrain and its functions.
It is the most complex or specialized part of the brain. It consists of cerebrum. The main functions
of forebrain are as follows:
(i) Main thinking part of the brain and cognitive functions like language and learning.
(ii) Controls the voluntary actions.
(iii) Stores information (memory).
(iv) Receives sensory impulses from various parts of the body and integrate it. There are seperate areas of association where sensory information is interpreted.
(v) It is the centre associated with hunger, thirst, fullness and other feelings.
what is hnid brain and functions
(i) Cerebellum: maintains posture and balance of body, precision of voluntary actions. e.g., picking pen.
(ii) Medulla: Controls involuntary actions. e.g., blood pressure, salivation, vomiting.
(iii) Pons: Controls involuntary actions and helps in regulation of sleep cycle and respiration. bridge between mid and hind brain
how is brain protected
the body is designed
so that the brain sits inside a bony box. Inside the box, the brain is
contained in a fluid-filled balloon which provides further shock
absorption.
what is the vertebral column
vertebral column is a bony segmented strcuture that protects the spinal cord.
how does nervous tissue cause action
*The point where the muscle fibre comes into contact with the motor neuron carrying the nervous impulse from the central nervous system is called the neuromuscular junction. The transmission of signals take place through the neurotransmitter like the same way betweeen two neurons.
*When a nerve impulse (information) reaches the muscles through the neuromuscular junction, the muscles show the action (response).
The muscles show the action/response by contraction and relaxation of the special muscle proteins.
*Muscle cells have special contractive proteins that are capable of contracting in response to the nervous impulse.
*This their shape, arrangement,size of the proteins in the cell changes, which leads the muscle to contract and causing movement
