Control and Coordination Test -10

Cerebellum is responsible for precision of voluntary actions and maintaining the posture and balance of the body. It is responsible for activities like walking in a straight line, riding a bicycle, picking up a pencil.

Damage to the cerebellum does not cause paralysis, but instead produces disorders in fine movement, equilibrium, posture, and motor learning.

Damage to a discrete part of the brain in the left frontal lobe in the cerebrum called the Broca's area affects the use of speech and language.

The cerebellum coordinates voluntary movements such as posture, balance, coordination, and speech, resulting in smooth and balanced muscular activity.

Damage to the cerebellum can lead to:

 

1) loss of coordination of motor movement

2) the inability to judge distance and when to stop

3) the inability to perform rapid alternating movements

4) movement tremors

5) staggering, wide based walking

6) abnormal eye movement.

• The nerve cells are known as neurons.

• They carry electrical impulses.

• Neurons are the basic unit of the nervous system.

• Every neuron is made of a cell body (also called soma), dendrites and an axon. Dendrites and axons are nerve fibers.

• Neurons, or nerve cells that carry nerve impulses, are made up of the cell body, the axon, and several dendrites.

• The cell body contains the nucleus and other organelles.

• Dendrites receive nerve impulses from other cells.

• Axons pass the nerve impulses on to other cells through axon terminal.

• Every neuron is made of a cell body (also called soma), dendrites and an axon.

• Dendrites receive nerve impulses from other cells.

• Axons pass the nerve impulses on to other cells through axon terminal.

Phototropism is the growth of organisms in response to light. It is most often observed in plants but can also occur in other organisms such as fungi. The cells on the plant that are farthest from the light have a chemical called auxin that reacts when phototropism occurs.

The cranium, in human beings, is formed by eight bones of which two are paired and the face is made up of 14 bones.

• The sensory and motor fibres of the spinal nerves form a reflex arc. This type of reflexive behaviour occurs when a message from afferent fibres causes a motor reaction before going to the brain. 
  
  
• For example, if we touch a hot burner on the stove, sensory information about the temperature of the burner travels along spinal nerves to the spinal cord and are carried directly to their motor nuclei by interneurons; the motor command goes out along the axons of the lower motor neuron causing to move our hand away from the stove.
  
  
•  As messages do not have to travel up to the brain to be processed, reactions mediated by this reflex arc can occur very rapidly.
  
  Hence, Option A is correct.

A normal human brain weighs on average about 1.5 kg (3.3 lb) with a volume of around 1130 cubic centimetres ($$cm^3$$) in women and 1260 $$cm^3$$ in men.

Correct option: A

There are two major female sex hormones: estrogen and progesterone. Both of these are steroid hormones. The primary source of these hormones is the ovaries. 

Thigmotropism is the growth response of a plant in response to external stimuli like touch or contact with a foreign object. The coiling of garden pea tendrils around any external support is an example of thigmotropism.