Podcast
Questions and Answers
What is the main function of the cell body (soma) in a neuron?
What is the main function of the cell body (soma) in a neuron?
- Control the activity of the whole neuron (correct)
- Connect with muscle or glands
- Conduct impulses towards the cell body
- Receive information from axon
Which cranial nerve is responsible for taste sensation?
Which cranial nerve is responsible for taste sensation?
- C X - Vagus nerve
- C III - Oculomotor nerve
- C XII - Hypoglossal nerve
- C IX - Glossopharyngeal nerve (correct)
Which type of neuron carries impulses from the environment to the central nervous system?
Which type of neuron carries impulses from the environment to the central nervous system?
- Afferent neuron (correct)
- Interneuron
- Efferent neuron
- Motor neuron
Which of the following cranial nerves is purely motor?
Which of the following cranial nerves is purely motor?
What junction is formed when an axon terminates at a muscle?
What junction is formed when an axon terminates at a muscle?
Which component of the reflex pathway is responsible for processing the information received?
Which component of the reflex pathway is responsible for processing the information received?
From where does the sympathetic nervous system originate?
From where does the sympathetic nervous system originate?
What is the role of interneurons in the nervous system?
What is the role of interneurons in the nervous system?
What is the function of the accessory nerve (C XI)?
What is the function of the accessory nerve (C XI)?
Which segment of the spinal cord is associated with the parasympathetic nervous system?
Which segment of the spinal cord is associated with the parasympathetic nervous system?
What type of neuron is responsible for carrying impulses from the CNS to effector organs?
What type of neuron is responsible for carrying impulses from the CNS to effector organs?
What is a reflex arc primarily responsible for?
What is a reflex arc primarily responsible for?
How many percent of nerve cells are interneurons in the nervous system?
How many percent of nerve cells are interneurons in the nervous system?
How many pairs of spinal nerves are there in the human body?
How many pairs of spinal nerves are there in the human body?
Which part of the nervous system is involved in voluntary control?
Which part of the nervous system is involved in voluntary control?
Which cranial nerve is responsible for the sense of smell?
Which cranial nerve is responsible for the sense of smell?
What is the total number of pairs of cranial nerves in humans?
What is the total number of pairs of cranial nerves in humans?
Which cranial nerve controls eye movement?
Which cranial nerve controls eye movement?
Which component is part of the brainstem?
Which component is part of the brainstem?
Which of the following cranial nerves are involved in the parasympathetic nervous system?
Which of the following cranial nerves are involved in the parasympathetic nervous system?
What is the origin of the sympathetic nervous system at the spinal level?
What is the origin of the sympathetic nervous system at the spinal level?
What characterizes all spinal nerves in terms of function?
What characterizes all spinal nerves in terms of function?
Which cranial nerves are identified as purely motor?
Which cranial nerves are identified as purely motor?
Which statement best describes the role of afferent neurons in the nervous system?
Which statement best describes the role of afferent neurons in the nervous system?
What is the primary function of the interneurons located within the central nervous system?
What is the primary function of the interneurons located within the central nervous system?
In reflex pathway, which component is responsible for reacting to a stimulus?
In reflex pathway, which component is responsible for reacting to a stimulus?
Which part of a neuron conducts impulses away from the cell body?
Which part of a neuron conducts impulses away from the cell body?
Which type of junction is formed between an axon and another neuron?
Which type of junction is formed between an axon and another neuron?
How many segments compose the spinal cord?
How many segments compose the spinal cord?
Which of the following best defines a reflex arc?
Which of the following best defines a reflex arc?
Which of the following statements about axons is false?
Which of the following statements about axons is false?
What constitutes the primary anatomical unit of the nervous system?
What constitutes the primary anatomical unit of the nervous system?
What division of the nervous system is responsible for involuntary control?
What division of the nervous system is responsible for involuntary control?
Which cranial nerve is responsible for controlling the eye's moving ability?
Which cranial nerve is responsible for controlling the eye's moving ability?
Which part of the spinal cord has the fewest associated pairs of spinal nerves?
Which part of the spinal cord has the fewest associated pairs of spinal nerves?
Which nervous system component connects to glands and cardiac muscles?
Which nervous system component connects to glands and cardiac muscles?
Which structure is NOT part of the brainstem?
Which structure is NOT part of the brainstem?
Study Notes
The Nervous System
- The nervous system controls body functions by receiving information, integrating it, and determining a response.
Structure and Components of a Neuron
- Neuron is the structural unit of the nervous system.
- Cell body (soma) controls the activity of the whole neuron.
- Cell processes are responsible for transmitting information.
- Dendrites are multiple, short processes that receive impulses and conduct them towards the cell body.
- Axon is a single, long process that conducts impulses away from the cell body.
- Axon Termination connects to:
- Muscle (neuro-muscular junction)
- Gland (neuro-epithelial junction)
- Another neuron (neuro-neural junction)
Types of Neurons
- Afferent (sensory) neuron: Carries impulses from receptors to the central nervous system (CNS).
- Efferent (motor) neuron: Carries impulses from the CNS to effector organs.
- Interneuron (associative neuron):
- Located inside the CNS.
- Acts as a link between neurons.
- Constitutes 99% of nerve cells.
Reflexes and the Reflex Arc
- Reflex: An involuntary programmed response to a stimulus.
- Reflex arc: The functional unit of the nervous system responsible for reflexes.
- Components of the reflex arc:
- Receptors receive stimuli.
- Afferent (sensory) neuron transmits information to the CNS.
- Center in the CNS integrates the information.
- Efferent (motor) neuron transmits information to effector organs.
- Effectors (muscles or glands) carry out the response.
Central Nervous System
- The CNS is protected by bones: skull and vertebral column.
Components of the CNS
-
Brain:
- Cerebrum:
- Cerebral cortex: The outer layer responsible for higher cognitive functions.
- Subcortical centers:
- Thalamus: Relay station for sensory information.
- Hypothalamus: Regulates homeostasis and many vital functions.
- Basal ganglia: Controls movement and coordination.
- Brain stem:
- Midbrain: Connects the forebrain to the hindbrain.
- Pons: Involved in sleep, breathing, and other functions.
- Medulla: Controls vital functions like breathing, heart rate, and blood pressure.
- Cerebellum: Coordinates movement and balance.
- Cerebrum:
-
Spinal Cord:
- 31 segments, each giving rise to a pair of spinal nerves.
- Segments:
- 8 Cervical
- 12 Thoracic
- 5 Lumbar
- 5 Sacral
- 1 Coccygeal
Peripheral Nervous System
- Connects the CNS to other tissues via nerves.
Anatomical Classification of the Peripheral Nervous System
- Cranial nerves: 12 pairs connected to the brain
- Spinal nerves: 31 pairs connected to the spinal cord.
Physiological Classification of the Peripheral Nervous System
- Somatic nervous system:
- Voluntary control.
- Connects to skeletal muscles, skin, tendons, bones, and joints.
- Autonomic nervous system:
- Involuntary control.
- Connects to smooth muscles, cardiac muscles, and glands.
Cranial Nerves
- 12 pairs connected to the brain.
- They can be sensory, motor or mixed.
- I (Olfactory): Smell.
- II (Optic): Vision.
- III (Oculomotor): Moving the eyeball.
- IV (Trochlear): Moving the eyeball.
- V (Trigeminal): Sensory to face, motor for mastication muscles.
- VI (Abducent): Motor to eye muscles.
- VII (Facial): Motor to muscles of the face.
- VIII (Auditory): Hearing and equilibrium.
- IX (Glossopharyngeal): Taste sensation, secretory to salivary glands.
- X (Vagus): Sensory and motor to muscles of thoracic and abdominal viscera.
- XI (Accessory): Motor to muscles of the back of the neck.
- XII (Hypoglossal): Motor to muscles of the tongue.
Spinal Nerves
- 31 pairs connected to the spinal cord.
- Roots:
- Dorsal root: Sensory fibers.
- Ventral root: Motor fibers.
- All spinal nerves are mixed nerves (sensory and motor).
Autonomic Nervous System
- Two divisions:
- Sympathetic: Fight or flight response.
- Parasympathetic: Rest and digest response.
Origin of the Autonomic Nervous System
- Sympathetic nervous system:
- Thoracic and upper 3 lumbar segments of the spinal cord.
- Parasympathetic nervous system:
- Cranial part: 3, 7, 9 and 10 cranial nerves.
- Sacral part: S2, S3, S4 (pelvic nerve).
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