Control and coordination 1

Question 1

define coordination

Answer 1

Coordination is the
process through which two or more organs interact and complement the
functions of one another

Question 2

describe neural systems in animals

Answer 2

The neural system of all animals is composed of highly specialised cells called
neurons which can detect, receive and transmit different kinds of stimuli.
The neural organisation is very simple in lower invertebrates. For
example, in Hydra it is composed of a network of neurons. The neural
system is better organised in insects, where a brain is present along with
a number of ganglia and neural tissues. The vertebrates have a more
developed neural system.

Question 3

what are the 2 main parts of the human nervous system

Answer 3

The human neural system is divided into two parts :
(i) the central neural system (CNS)
(ii) the peripheral neural system (PNS)
The CNS includes the brain and the spinal cord and is the site of
information processing and control. The PNS comprises of all the nerves
of the body associated with the CNS (brain and spinal cord).It forms a connection between body organs and the brain and spinal cord.

Question 4

what are the 2 types of nerves present in PNS

Answer 4

The nerve
fibres of the PNS are of two types :
(a) afferent fibres
(b) efferent fibres
The afferent nerve fibres transmit impulses from tissues/organs to
the CNS and the efferent fibres transmit regulatory impulses from the
CNS to the concerned peripheral tissues/organs.

Question 5

how is PNS further divided into 2 classes?

Answer 5

The PNS is divided into two divisions called somatic neural system
and autonomic neural system. The somatic neural system relays
impulses from the CNS to skeletal muscles(voluntary action) while the autonomic neural
system transmits impulses from the CNS to the involuntary organs and
smooth muscles of the body(involuntarty actions). The autonomic neural system is further
classified into sympathetic neural system and parasympathetic neural
system.

Question 6

what is visceral nervous system

Answer 6

Visceral nervous system is the part of the peripheral nervous system
that comprises the whole complex of nerves, fibres, ganglia, and plexuses
by which impulses travel from the central nervous system to the viscera
and from the viscera to the central nervous system.

Question 7

what are the main parts of a neuron

Answer 7

A neuron is a microscopic structure composed of three major parts, namely,
cell body, dendrites and axon (Figure 21.1). The cell body contains cytoplasm, bound by a cell membrane called neurilemma
with typical cell organelles and certain granular bodies called Nissl’s granules. Nissl’s granules represent RER and hence shows that neurons are actively involved in protein synthesis.

Short fibres which branch repeatedly and project out of the cell body also contain Nissl’s granules and are called dendrites. These
fibres transmit impulses towards the cell body. The
axon is a long fibre, the distal end of which is branched.
Each branch terminates as a bulb-like structure called
synaptic knob which possess synaptic vesicles
containing chemicals called neurotransmitters. The
axons transmit nerve impulses away from the cell body
to a synapse or to a neuro-muscular junction.

Question 8

wht are the types of neurons

Answer 8

Based
on the number of axon and dendrites, the neurons are
divided into three types, i.e., multipolar (with one axon
and two or more dendrites; found in the cerebral cortex),
bipolar (with one axon and one dendrite, found in the
retina of eye) and unipolar (cell body with one axon
only; found usually in the embryonic stage).

Question 9

what are schwann cells and myelin sheath

Answer 9

. The myelinated nerve fibres are enveloped
with Schwann cells, which form a myelin sheath
around the axon. The gaps between two adjacent
myelin sheaths are called nodes of Ranvier

Question 10

differentiate betweem myelinated and non myelinated schwann cell

Answer 10

-Myelinated neurons have schwann cells enveloping their axons and are covered with myelin sheath.
-Node of ranvier is present
-the conduction of nerve impulses is much faster.
Myelinated nerve fibres are found in spinal and cranial
nerves.

• Non myelinated nerve fibres have schwann cells enveloping the axon but they do not have myelin sheath.
• Nodes of ranvier are absent
• The conduction of nerve impulses is much slower.
  -s commonly found in
  autonomous and the somatic neural systems.