Control and Coordination - 6.16.16.16.1 ANIMALS – NERVOUS SYSTEMANIMALS – NERVOUS SYSTEMANIMALS – NERVOUS SYSTEMANIMALS – NERVOUS SYSTEMANIMALS – NERVOUS SYSTEM
Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
The Neuron is the structural and functional unit of the nervous system. It consists of the Cell Body (Cyton), Dendrites (receive signals), and Axon (transmits signals).
Nerve Impulse Transmission: Information is acquired at the dendritic tip, sets off a chemical reaction that creates an electrical impulse. This impulse travels from the dendrite to the cell body, and then along the axon to its end.
Synapse: The microscopic gap between the axon terminal of one neuron and the dendrite of the next. At the synapse, electrical signals are converted into chemical signals (neurotransmitters) to cross the gap.
Reflex Action: An extremely quick, automated, and involuntary response to a stimulus (e.g., withdrawing a hand from a hot object). The pathway is called the Reflex Arc.
The Central Nervous System (CNS) consists of the Brain and Spinal Cord. The Peripheral Nervous System (PNS) consists of Cranial nerves (from brain) and Spinal nerves (from spinal cord).
Brain Parts: The Forebrain (Cerebrum) is the main thinking part; the Midbrain controls certain involuntary actions; the Hindbrain consists of the Cerebellum (balance), Medulla (involuntary actions like blood pressure), and Pons (respiration).
Protection: The brain is housed in a bony box called the Cranium and is cushioned by Cerebrospinal Fluid (CSF).
📐Formulae
💡Examples
Problem 1:
Identify the part of the brain responsible for the following: (i) Maintaining posture and balance, (ii) Beating of the heart, (iii) Thinking and memory.
Solution:
(i) Cerebellum (part of Hindbrain), (ii) Medulla (part of Hindbrain), (iii) Cerebrum (part of Forebrain).
Explanation:
The Cerebellum coordinates voluntary movements for precision; the Medulla controls autonomic/involuntary functions; the Cerebrum handles complex cognitive processes.
Problem 2:
How does the nervous tissue cause action (muscle movement)?
Solution:
When a nerve impulse reaches the muscle, the muscle fibers must move. Muscle cells have special proteins that change their shape and arrangement in the cell in response to nervous electrical impulses. This results in the shortening (contraction) of the muscle cell.
Explanation:
This is the point where the nervous system communicates with the muscular system, often called the Neuromuscular Junction.
Problem 3:
What is the difference between a reflex action and walking?
Solution:
A Reflex Action is an involuntary, rapid response to a stimulus mediated by the spinal cord (e.g., ), whereas Walking is a voluntary action controlled by the cerebellum and cerebrum based on conscious decision-making.
Explanation:
Reflexes are for survival and bypass the conscious brain to save time, while walking is a coordinated learned behavior.