Quick Review Flashcards - Click to flip and test your knowledge!
Question
What is the structural and functional unit of the human nervous system?
Answer
The neuron (or nerve cell).
Question
Name the three main parts that constitute a neuron.
Answer
The cell body (cyton), dendrites, and axon.
Question
Why do nerve cells lose the ability to divide?
Answer
They lack a centrosome.
Question
Term: Perikaryon
Answer
Definition: Another name for the cell body or cyton of a neuron.
Question
What is the function of dendrites in a neuron?
Answer
They conduct nerve impulses towards the cyton.
Question
Describe the function of the axon in a nerve cell.
Answer
It conducts nerve impulses away from the cyton.
Question
What is the white insulating sheath that often surrounds an axon called?
Answer
The myelin (or medullary) sheath.
Question
Name the outermost thin sheath that covers the myelin sheath of an axon.
Answer
The neurolemma.
Question
What are the periodic gaps found throughout the length of the myelin sheath called?
Answer
Nodes of Ranvier.
Question
Where are neurotransmitters stored within a neuron?
Answer
In the swollen end portions of axon terminals called bulbs.
Question
The microscopic gap between the axon terminals of one neuron and the dendrites of the next is the _____.
Answer
Synaptic cleft
Question
Define 'Stimulus' in the context of nervous activity.
Answer
An agent or sudden change in the environment that results in a change in an organism.
Question
What is an 'Impulse' in the nervous system?
Answer
A wave of electrical disturbance that sweeps over the nerve cell.
Question
What term describes the muscles or glands that contract or secrete substances upon receiving a nerve impulse?
Answer
Effectors.
Question
During the resting state, why is a nerve fibre considered to be in a 'polarised' state?
Answer
The outer side carries positive charges due to more $Na^+$ ions outside the membrane.
Question
What occurs during the process of 'depolarisation' in a nerve fibre?
Answer
The membrane becomes permeable to $Na^+$ ions, which move inwards and cause loss of polarisation.
Question
The 'sodium pump' uses energy from _____ to transport $Na^+$ ions back to the outside of the membrane.
Answer
ATP
Question
How does the speed of a nerve impulse (max $100$ metres per second) compare to the speed of electricity?
Answer
It is significantly slower than electricity, which travels at approximately $300,000$ kilometres per second.
Question
Concept: Synapse
Answer
Definition: The point of chemical communication between the axon terminals of one neuron and the dendrites of another.
Question
Which specific chemical is released at the terminal end of an axon to transmit an impulse across a synapse?
Answer
Acetylcholine.
Question
What happens to acetylcholine after it has stimulated a new impulse in the adjacent neuron?
Answer
It is broken down by an enzyme to prepare the synapse for the next transmission.
Question
What is the primary role of sensory (afferent) neurons?
Answer
They convey impulses from receptors to the main nervous system (brain or spinal cord).
Question
Which type of neuron interconnects sensory and motor neurons within the brain and spinal cord?
Answer
Association (connecting) neurons.
Question
Term: Nerve
Answer
Definition: A bundle of nerve fibres (axons) from separate neurons enclosed in a tubular sheath.
Question
What distinguishes a 'mixed nerve' from sensory or motor nerves?
Answer
It contains both sensory and motor fibres.
Question
Identify an example of a sensory nerve provided in the text.
Answer
The optic nerve.
Question
Define 'Ganglia' in the nervous system.
Answer
Aggregates of the cytons or cell bodies of nerve cells from which nerve fibres arise or enter.
Question
Which two major structures comprise the Central Nervous System (CNS)?
Answer
The brain and the spinal cord.
Question
What is the approximate weight of an adult human brain?
Answer
$1.35$ kg.
Question
Name the three membranous coverings (meninges) of the brain from outermost to innermost.
Answer
Dura mater, Arachnoid, and Pia mater.
Question
What is the clinical term for the inflammation of the meninges?
Answer
Meningitis.
Question
What fluid acts as a shock absorber for the brain and fills the central canal of the spinal cord?
Answer
Cerebrospinal fluid (CSF).
Question
Which part of the brain is the seat of intelligence, consciousness, and will-power?
Answer
The cerebrum.
Question
What is the function of the corpus callosum?
Answer
To transfer information between the two cerebral hemispheres.
Question
In the cerebrum, what are the ridges and grooves on the convoluted surface called?
Answer
The ridges are gyri and the grooves are sulci.
Question
Where is 'gray matter' located in the cerebrum, and what does it primarily contain?
Answer
It is in the outer portion (cortex) and contains the cell bodies of neurons.
Question
The inner portion of the cerebrum, known as white matter, mainly consists of _____.
Answer
Axons (nerve fibres)
Question
What is the primary function of the cerebellum?
Answer
To maintain body balance and coordinate muscular activity.
Question
Why does an intoxicated person walk clumsily?
Answer
Alcohol affects the cerebellum, making it unable to coordinate muscular movements properly.
Question
Which part of the brain controls vital involuntary activities like heartbeat and breathing?
Answer
The medulla oblongata.
Question
Identify the two components of the Diencephalon.
Answer
The thalamus and the hypothalamus.
Question
Which part of the brain serves as the control centre for body temperature and the pituitary gland?
Answer
The hypothalamus.
Question
What is the function of the Pons in the hindbrain?
Answer
It carries impulses from one hemisphere of the cerebellum to the other and coordinates muscular movements.
Question
Where does the spinal cord extend from and where does it end?
Answer
It extends from the medulla of the brain down to the level of the second lumbar vertebra.
Question
Contrast the arrangement of gray and white matter in the spinal cord versus the brain.
Answer
In the spinal cord, gray matter is inner and white matter is outer, which is the reverse of the brain's arrangement.
Question
Name one of the primary functions of the spinal cord regarding reflexes.
Answer
It controls reflexes below the neck.
Question
The Peripheral Nervous System (PNS) is divided into the Somatic Nervous System and the _____.
Answer
Autonomic Nervous System
Question
How many pairs of cranial nerves and spinal nerves are found in humans?
Answer
$12$ pairs of cranial nerves and $31$ pairs of spinal nerves.
Question
The Somatic Nervous System conveys information specifically to _____ muscles.
Answer
Skeletal (voluntary)
Question
What is the primary role of the Autonomic Nervous System (ANS)?
Answer
It controls the involuntary actions of internal organs like the heart and lungs.
Question
Which part of the Autonomic Nervous System prepares the body for 'fight or flight' (violent action)?
Answer
The sympathetic nervous system.
Question
How does the parasympathetic nervous system affect the heart rate compared to the sympathetic system?
Answer
It retards (slows) the heart rate, while the sympathetic system accelerates it.
Question
Which hormone stimulates the sympathetic nervous system during emergencies?
Answer
Adrenaline.
Question
What is the effect of the parasympathetic nervous system on the pupils of the eye?
Answer
It causes constriction.
Question
Define 'Reflex action'.
Answer
An automatic, quick, and involuntary response to a stimulus.
Question
What is a 'Natural (inborn) reflex'?
Answer
A reflex that is inherited from parents and requires no previous experience or learning.
Question
Provide an example of a conditioned (acquired) reflex.
Answer
Salivating at the sound of a bell (as in Pavlov's experiment) or typing on a keyboard.
Question
Who performed the classic experiment on dogs to demonstrate conditioned reflexes?
Answer
Ivan Pavlov.
Question
What is the shortest route an impulse can take from a receptor to an effector called?
Answer
A reflex arc.
Question
In a simple reflex arc, the impulse from the receptor is first carried by the _____ neuron.
Answer
Sensory (afferent)