Control and Coordination - Human Nervous System

Flashcards testing knowledge on Control and Coordination, covering the structure and functions of the nervous system, reflex actions, brain anatomy, and nerve transmission.

What is the definition of coordination in living organisms?

Coordination is the process by which different organs of a living organism work together in a controlled and efficient manner to respond to stimuli.

What is the structural and functional unit of the nervous system, and how long can it be?

The neuron (or nerve cell) is the structural and functional unit of the nervous system. It is the longest cell in the human body, with some reaching lengths of $90\text{--}100\,\text{cm}$.

What are the three main structural parts of a neuron?

The three main parts are: (i) Dendrites, (ii) Cell body or Cyton, and (iii) Axon.

What is the structure and function of dendrites?

Dendrites are protoplasmic, branched finger-like projections of the cell body that receive and transmit impulses.

How do sensory neurons, motor neurons, and relay neurons differ by function and location?

Sensory neurons carry impulses from sense organs to the brain or spinal cord; motor neurons carry impulses from the CNS to effector organs like muscles or glands; relay neurons connect sensory neurons to motor neurons and are located entirely within the brain and spinal cord.

What is a synapse?

A synapse is a small gap between two adjacent neurons where nerve impulses pass from one neuron to another in one direction via chemical neurotransmitters.

Why does the neuromuscular junction contain many mitochondria?

It contains many mitochondria to provide the energy required for the release of neurotransmitters and for muscle activity.

What are the two major limitations to the use of electrical impulses in animal bodies?

(i) Electrical impulses reach only cells connected by nervous tissue, not every cell in the body. (ii) Once an impulse is transmitted, the cell takes time to reset its mechanism before generating and transmitting a new impulse.

What is a reflex action, and which organ primarily monitors and controls it?

A reflex action is an automatic and rapid response to a stimulus that protects the body from damage without conscious thought. It is monitored and controlled majorly through the spinal cord.

What is a reflex arc, and what are its five main components?

A reflex arc is the pathway taken by nerve impulses in a reflex action. Its components are: (i) Sense organs/Receptors, (ii) Sensory (afferent) neuron, (iii) Spinal cord, (iv) Motor (efferent) neuron, and (v) Effectors or muscles.

What specific receptors are found in the eyes, ears, nose, and tongue?

Photoreceptors in the eyes (light), mechanoreceptors in the ears (sound), olfactory receptors in the nose (smell), and gustatory receptors in the tongue (taste).

What are the two main subdivisions of the Human Nervous System?

The Central Nervous System (CNS), comprising the brain and spinal cord, and the Peripheral Nervous System (PNS).

What are the three types of functional areas located in the cerebrum?

(i) Sensory areas (receive sensory impulses), (ii) Association areas (interpret sensory information relative to past experience), and (iii) Motor areas (send impulses to muscles and control voluntary movements).

What are the functions of the olfactory lobes and the hypothalamus in the forebrain?

Olfactory lobes are responsible for detecting smell. The hypothalamus controls body temperature, the urge to eat and drink, and other functions.

What is the function of the midbrain?

The midbrain connects the forebrain to the hindbrain and controls movements of the head, neck, and trunk to locate sounds, visual reflexes involved in focusing on objects, and reflex movements of eye muscles and pupil size.

What are the three parts of the hindbrain and their functions?

(i) Cerebellum: controls/coordinates muscular actions, voluntary movement precision, and body posture/equilibrium. (ii) Pons: takes part in respiration and relays impulses between brain parts. (iii) Medulla Oblongata: controls involuntary actions like breathing, blood pressure (BP), salivation, and vomiting.

Which parts of the brain combine to form the brain stem?

The midbrain and hindbrain together form the brain stem, which connects to the spinal cord.

How are the human brain and spinal cord protected from physical damage?

The brain sits inside a bony box called the cranium and is contained in a fluid-filled balloon for shock absorption. The spinal cord is protected by a hard, bumpy structure called the vertebral column or backbone.

How do muscle cells bring about movement in response to a nervous impulse?

Special proteins in muscle cells change both their shape and arrangement in response to nervous impulses, giving the muscle cells a shorter form and bringing about movement in the desired direction.

What three types of nerves make up the Peripheral Nervous System (PNS)?

(i) Cranial Nerves (emerge from brain to head), (ii) Spinal Nerves (arise from spinal cord to rest of body except head), and (iii) Visceral Nerves (arise mostly from spinal cord to internal organs).