Podcast
Questions and Answers
What is the basic structural and functional unit of the nervous system?
What is the basic structural and functional unit of the nervous system?
- Glial cell
- Neuron (correct)
- Muscle fiber
- Epithelial cell
Which part of the neuron typically carries signals away from the cell body?
Which part of the neuron typically carries signals away from the cell body?
- Cyton
- Dendrite
- Axon (correct)
- Synapse
What is the function of the myelin sheath?
What is the function of the myelin sheath?
- To insulate nerve fibers (correct)
- To protect the cyton
- To transmit signals chemically
- To produce neurotransmitters
Which type of nerve carries impulses from the sense organs to the brain or spinal cord?
Which type of nerve carries impulses from the sense organs to the brain or spinal cord?
Which of the following is an example of a motor nerve?
Which of the following is an example of a motor nerve?
Nerves that contain both sensory and motor fibers are called?
Nerves that contain both sensory and motor fibers are called?
How many pairs of cranial nerves do humans have?
How many pairs of cranial nerves do humans have?
Which of the following are the two main structural components of the central nervous system?
Which of the following are the two main structural components of the central nervous system?
What is the main function of the cerebrum?
What is the main function of the cerebrum?
Which part of the brain is responsible for maintaining balance?
Which part of the brain is responsible for maintaining balance?
The medulla oblongata controls what?
The medulla oblongata controls what?
What protects the spinal cord?
What protects the spinal cord?
What is a stimulus?
What is a stimulus?
Pulling your hand away from a hot stove is an example of what?
Pulling your hand away from a hot stove is an example of what?
What are the eyes, skin, tongue, ears, and nose known as?
What are the eyes, skin, tongue, ears, and nose known as?
What are actions controlled by the brain called?
What are actions controlled by the brain called?
What part of the body controls reflex actions?
What part of the body controls reflex actions?
Which of these is an example of a reflex action?
Which of these is an example of a reflex action?
The inner surface of our fingertips is very sensitive because it contains many?
The inner surface of our fingertips is very sensitive because it contains many?
How does the myelin sheath contribute to nerve impulse transmission?
How does the myelin sheath contribute to nerve impulse transmission?
What distinguishes cranial nerves from spinal nerves in terms of their origin?
What distinguishes cranial nerves from spinal nerves in terms of their origin?
Which of the following activities is primarily controlled by the cerebrum?
Which of the following activities is primarily controlled by the cerebrum?
What is the primary function of the spinal cord's white matter?
What is the primary function of the spinal cord's white matter?
How does the endocrine system differ from the nervous system in transmitting messages?
How does the endocrine system differ from the nervous system in transmitting messages?
Which of the following correctly describes the sequence of events in a reflex arc after touching a hot object?
Which of the following correctly describes the sequence of events in a reflex arc after touching a hot object?
What is the role of receptors present in sense organs?
What is the role of receptors present in sense organs?
Which part of the brain is critical for coordinating muscle movements and maintaining balance?
Which part of the brain is critical for coordinating muscle movements and maintaining balance?
What structural feature increases the surface area of the cerebrum to accommodate a large number of nerve cells?
What structural feature increases the surface area of the cerebrum to accommodate a large number of nerve cells?
How does the spinal cord facilitate communication between the brain and the body?
How does the spinal cord facilitate communication between the brain and the body?
If a person quickly pulls their hand away from a hot stove, what type of response is this action?
If a person quickly pulls their hand away from a hot stove, what type of response is this action?
What is the primary difference between the composition of gray matter and white matter in the spinal cord?
What is the primary difference between the composition of gray matter and white matter in the spinal cord?
Which of the following accurately describes the function of a motor neuron?
Which of the following accurately describes the function of a motor neuron?
What is the correct classification of a nerve that contains both sensory and motor fibers?
What is the correct classification of a nerve that contains both sensory and motor fibers?
In the context of the nervous system, what is the best definition of a 'stimulus'?
In the context of the nervous system, what is the best definition of a 'stimulus'?
Which of the following lists the components of the human central nervous system?
Which of the following lists the components of the human central nervous system?
How do voluntary actions differ from reflex actions with respect to the involvement of the brain?
How do voluntary actions differ from reflex actions with respect to the involvement of the brain?
What is the primary function of the medulla oblongata?
What is the primary function of the medulla oblongata?
Which of the following describes how an impulse travels?
Which of the following describes how an impulse travels?
Which of the following accurately describes the role of effectors in the nervous system?
Which of the following accurately describes the role of effectors in the nervous system?
If the myelin sheath around an axon is damaged, which of the following functions would be most directly impaired?
If the myelin sheath around an axon is damaged, which of the following functions would be most directly impaired?
How would severing a mixed nerve impact bodily functions?
How would severing a mixed nerve impact bodily functions?
A patient has suffered damage to their cerebellum. Which of the following symptoms would you expect to observe?
A patient has suffered damage to their cerebellum. Which of the following symptoms would you expect to observe?
What would be the likely outcome of damage restricted to the white matter of the spinal cord?
What would be the likely outcome of damage restricted to the white matter of the spinal cord?
How does the brain's cerebrum maximize its surface area to accommodate a large number of neurons?
How does the brain's cerebrum maximize its surface area to accommodate a large number of neurons?
Following a stroke, a patient exhibits difficulty understanding spoken language but can still speak fluently, although their speech lacks meaning. Which area of the brain is most likely affected?
Following a stroke, a patient exhibits difficulty understanding spoken language but can still speak fluently, although their speech lacks meaning. Which area of the brain is most likely affected?
In the context of a reflex arc, what would be the most significant consequence of a damaged sensory neuron?
In the context of a reflex arc, what would be the most significant consequence of a damaged sensory neuron?
How does the endocrine system's method of communication differ fundamentally from that of the nervous system in coordinating bodily functions?
How does the endocrine system's method of communication differ fundamentally from that of the nervous system in coordinating bodily functions?
Which of the following correctly describes the interaction between a stimulus, receptor, and effector in a neural pathway?
Which of the following correctly describes the interaction between a stimulus, receptor, and effector in a neural pathway?
What is the functional significance of the spinal cord being protected by the vertebral column?
What is the functional significance of the spinal cord being protected by the vertebral column?
A nerve cell, also known as a neuron, consists of three main parts: cyton, axon, and dendrites.
A nerve cell, also known as a neuron, consists of three main parts: cyton, axon, and dendrites.
Nerve fibres are formed when muscle cells are joined end to end.
Nerve fibres are formed when muscle cells are joined end to end.
The myelin sheath insulates the axon and prevents the mixing of impulses in adjacent nerve fibres.
The myelin sheath insulates the axon and prevents the mixing of impulses in adjacent nerve fibres.
Sensory nerves carry impulses from the brain to the muscles.
Sensory nerves carry impulses from the brain to the muscles.
Motor nerves contain only motor nerve fibres.
Motor nerves contain only motor nerve fibres.
Mixed nerves carry both sensory and motor fibres.
Mixed nerves carry both sensory and motor fibres.
Cranial nerves originate from the spinal cord.
Cranial nerves originate from the spinal cord.
Humans have 12 pairs of spinal nerves.
Humans have 12 pairs of spinal nerves.
The brain and spinal cord are components of the peripheral nervous system.
The brain and spinal cord are components of the peripheral nervous system.
The cerebrum is the smallest part of the brain.
The cerebrum is the smallest part of the brain.
The cerebrum controls mental activities like thinking and reasoning.
The cerebrum controls mental activities like thinking and reasoning.
The cerebellum is located at the base of the skull above the spinal cord.
The cerebellum is located at the base of the skull above the spinal cord.
The medulla oblongata controls vital activities such as heartbeat and breathing.
The medulla oblongata controls vital activities such as heartbeat and breathing.
The spinal cord is protected by the skull.
The spinal cord is protected by the skull.
A stimulus is any change in the external environment of an organism that results in a change in the body's activity.
A stimulus is any change in the external environment of an organism that results in a change in the body's activity.
Myelin sheaths facilitate the mixing of impulses between adjacent nerve fibers.
Myelin sheaths facilitate the mixing of impulses between adjacent nerve fibers.
Sensory nerves exclusively contain sensory fibers, carrying impulses from the brain to sense organs.
Sensory nerves exclusively contain sensory fibers, carrying impulses from the brain to sense organs.
There are a total of 24 pairs of cranial nerves in humans.
There are a total of 24 pairs of cranial nerves in humans.
Spinal nerves originate from the brain and extend to various parts of the body below the head.
Spinal nerves originate from the brain and extend to various parts of the body below the head.
The cerebrum, cerebellum, and medulla oblongata are the three primary components of the brain.
The cerebrum, cerebellum, and medulla oblongata are the three primary components of the brain.
The cerebrum's smooth surface maximizes surface area for accommodating numerous nerve cells.
The cerebrum's smooth surface maximizes surface area for accommodating numerous nerve cells.
The cerebellum is primarily responsible for reasoning and memory.
The cerebellum is primarily responsible for reasoning and memory.
The medulla oblongata, located at the top of the skull, connects the brain to the spinal cord.
The medulla oblongata, located at the top of the skull, connects the brain to the spinal cord.
The spinal cord extends from the cerebrum and runs down the entire length of the vertebral column.
The spinal cord extends from the cerebrum and runs down the entire length of the vertebral column.
The gray matter of the spinal cord is primarily made up of nerve fibers.
The gray matter of the spinal cord is primarily made up of nerve fibers.
The endocrine system transmits messages faster than the nervous system because hormones travel directly to target organs.
The endocrine system transmits messages faster than the nervous system because hormones travel directly to target organs.
A stimulus always results in a voluntary action.
A stimulus always results in a voluntary action.
Effectors are sense organs that detect stimuli and transmit impulses to the central nervous system.
Effectors are sense organs that detect stimuli and transmit impulses to the central nervous system.
Reflex actions involve the brain to facilitate a quick and controlled response to a stimulus.
Reflex actions involve the brain to facilitate a quick and controlled response to a stimulus.
The sensitivity of fingertips is primarily due to a lower concentration of nerve endings compared to other areas of the skin.
The sensitivity of fingertips is primarily due to a lower concentration of nerve endings compared to other areas of the skin.
The basic structural and functional unit of the nervous system is a nerve cell or a ______.
The basic structural and functional unit of the nervous system is a nerve cell or a ______.
Nerve cells are joined end to end to form long nerve ______.
Nerve cells are joined end to end to form long nerve ______.
A number of nerve fibres are bundled together in a tubular sheath to form a ______.
A number of nerve fibres are bundled together in a tubular sheath to form a ______.
The layer of myelin sheath over the axon acts as an ______.
The layer of myelin sheath over the axon acts as an ______.
[Blank] nerves bring impulses from the sense organs to the brain or the spinal cord.
[Blank] nerves bring impulses from the sense organs to the brain or the spinal cord.
[Blank] nerves carry impulses from the brain or the spinal cord to the muscles or glands.
[Blank] nerves carry impulses from the brain or the spinal cord to the muscles or glands.
Nerves arising from the brain and reach the organs in the head region are ______ nerves.
Nerves arising from the brain and reach the organs in the head region are ______ nerves.
Nerves arising from the spinal cord and reach various parts of the body are ______ nerves.
Nerves arising from the spinal cord and reach various parts of the body are ______ nerves.
The brain and spinal cord are the two main structural components of the ______ nervous system.
The brain and spinal cord are the two main structural components of the ______ nervous system.
The ______ is the main control centre of the nervous system.
The ______ is the main control centre of the nervous system.
The ______ controls mental activities like thinking and reasoning.
The ______ controls mental activities like thinking and reasoning.
The ______ maintains balance of the body and coordinates muscular activities.
The ______ maintains balance of the body and coordinates muscular activities.
The lowest part of the brain, the ______, controls vital activities such as heartbeat and breathing.
The lowest part of the brain, the ______, controls vital activities such as heartbeat and breathing.
Any change in the environment of an organism that results in a change in the activity of the body is called ______.
Any change in the environment of an organism that results in a change in the activity of the body is called ______.
The actions which are under the control of the spinal cord are called ______ actions.
The actions which are under the control of the spinal cord are called ______ actions.
The layer of ______ sheath over the axon acts as an insulator, preventing the mixing of impulses in adjacent nerve fibres.
The layer of ______ sheath over the axon acts as an insulator, preventing the mixing of impulses in adjacent nerve fibres.
[Blank] nerves bring impulses from the sense organs to the brain or the spinal cord and contain only ______ fibres.
[Blank] nerves bring impulses from the sense organs to the brain or the spinal cord and contain only ______ fibres.
Motor nerves carry impulses from the brain or the spinal cord to the muscles or ______, containing only motor nerve fibres.
Motor nerves carry impulses from the brain or the spinal cord to the muscles or ______, containing only motor nerve fibres.
Mixed nerves carry both sensory and ______ fibres, allowing for bidirectional communication between the central nervous system and the periphery.
Mixed nerves carry both sensory and ______ fibres, allowing for bidirectional communication between the central nervous system and the periphery.
The ______, located just under the cerebrum at the back of the head, maintains balance and coordinates muscular activities.
The ______, located just under the cerebrum at the back of the head, maintains balance and coordinates muscular activities.
The ______ oblongata, the lowest part of the brain, joins the brain to the spinal cord and controls vital activities like heartbeat and breathing.
The ______ oblongata, the lowest part of the brain, joins the brain to the spinal cord and controls vital activities like heartbeat and breathing.
The spinal cord, protected by the vertebral column, extends from the medulla oblongata and contains a central canal filled with ______ fluid.
The spinal cord, protected by the vertebral column, extends from the medulla oblongata and contains a central canal filled with ______ fluid.
In the spinal cord, the ______ matter, made up of cell bodies of the neurons, surrounds the central canal.
In the spinal cord, the ______ matter, made up of cell bodies of the neurons, surrounds the central canal.
Unlike the nervous system, the endocrine system sends messages in the form of ______ through the blood, resulting in slower transmission.
Unlike the nervous system, the endocrine system sends messages in the form of ______ through the blood, resulting in slower transmission.
Sense organs detect a stimulus and transmit the stimulus through the nerves to ______.
Sense organs detect a stimulus and transmit the stimulus through the nerves to ______.
Actions controlled by the brain are called ______ actions, while those under the control of the spinal cord are reflex actions.
Actions controlled by the brain are called ______ actions, while those under the control of the spinal cord are reflex actions.
The path that an impulse takes in a reflex action is called a ______ arc, enabling quick, automatic responses.
The path that an impulse takes in a reflex action is called a ______ arc, enabling quick, automatic responses.
Special cells known as ______ in the sense organs receive information and transmit it to the nerves, which then send it to the brain.
Special cells known as ______ in the sense organs receive information and transmit it to the nerves, which then send it to the brain.
Name the three main parts of a nerve cell or neuron.
Name the three main parts of a nerve cell or neuron.
What type of nerve carries impulses from sense organs to the brain?
What type of nerve carries impulses from sense organs to the brain?
What type of nerve carries impulses from the brain to muscles or glands?
What type of nerve carries impulses from the brain to muscles or glands?
Name the two types of nerves based on their origin.
Name the two types of nerves based on their origin.
What are the two main structural components of the central nervous system?
What are the two main structural components of the central nervous system?
Name the uppermost and largest part of the brain.
Name the uppermost and largest part of the brain.
Which part of the brain maintains balance and coordinates muscular activities?
Which part of the brain maintains balance and coordinates muscular activities?
What part of the brain controls vital activities like heartbeat and breathing?
What part of the brain controls vital activities like heartbeat and breathing?
What is any change in the environment of an organism that results in a change in the activity of the body called?
What is any change in the environment of an organism that results in a change in the activity of the body called?
What is any activity due to the stimulus called?
What is any activity due to the stimulus called?
What is a wave of electrical disturbance that runs through the nerves called?
What is a wave of electrical disturbance that runs through the nerves called?
Name an example of a voluntary action.
Name an example of a voluntary action.
What is an involuntary response to a stimulus called?
What is an involuntary response to a stimulus called?
Explain the significance of the myelin sheath that surrounds the axon of a nerve fiber?
Explain the significance of the myelin sheath that surrounds the axon of a nerve fiber?
Describe how sensory and motor nerves differ in both structure and function, giving an example of each?
Describe how sensory and motor nerves differ in both structure and function, giving an example of each?
Contrast cranial and spinal nerves based on their origin and the regions of the body they serve?
Contrast cranial and spinal nerves based on their origin and the regions of the body they serve?
If the cerebrum were damaged what resulting impairments might be evident in an individual's behaviour?
If the cerebrum were damaged what resulting impairments might be evident in an individual's behaviour?
What are the likely consequences if the cerebellum is damaged due to an accident?
What are the likely consequences if the cerebellum is damaged due to an accident?
How would damage to the medulla oblongata affect an individual's vital functions?
How would damage to the medulla oblongata affect an individual's vital functions?
Describe the arrangement of grey matter and white matter in the spinal cord, and explain the functional significance of this arrangement?
Describe the arrangement of grey matter and white matter in the spinal cord, and explain the functional significance of this arrangement?
Explain how the nervous system and the endocrine system differ in terms of message transmission, components, and speed of response, and which uses hormones?
Explain how the nervous system and the endocrine system differ in terms of message transmission, components, and speed of response, and which uses hormones?
Differentiate between a stimulus and a response, providing a specific example to illustrate the relationship between them?
Differentiate between a stimulus and a response, providing a specific example to illustrate the relationship between them?
Describe the role of receptors and effectors in the nervous system, giving an example of each?
Describe the role of receptors and effectors in the nervous system, giving an example of each?
Explain the difference between voluntary actions and reflex actions, in terms of the parts of the nervous system involved and the speed of the response.
Explain the difference between voluntary actions and reflex actions, in terms of the parts of the nervous system involved and the speed of the response.
Outline the sequence of events that occur in a reflex arc when someone touches a hot object?
Outline the sequence of events that occur in a reflex arc when someone touches a hot object?
What is the role of motor neurons within the nervous system?
What is the role of motor neurons within the nervous system?
Explain how sense organs facilitate our ability to perceive and respond to changes in our environment?
Explain how sense organs facilitate our ability to perceive and respond to changes in our environment?
Our fingertips are very sensitive to external stimuli. What structural feature makes them so sensitive?
Our fingertips are very sensitive to external stimuli. What structural feature makes them so sensitive?
Describe the functional significance of the myelin sheath that surrounds some nerve fibers and what happens if it degrades?
Describe the functional significance of the myelin sheath that surrounds some nerve fibers and what happens if it degrades?
How do cranial nerves and spinal nerves differ in their origin and the regions of the body they serve?
How do cranial nerves and spinal nerves differ in their origin and the regions of the body they serve?
What are the functional differences between the cerebrum, cerebellum, and medulla oblongata?
What are the functional differences between the cerebrum, cerebellum, and medulla oblongata?
Explain the arrangement of grey matter and white matter and their respective functions within the spinal cord.
Explain the arrangement of grey matter and white matter and their respective functions within the spinal cord.
Compare and contrast the mechanisms and speed of message transmission in the nervous system versus the endocrine system.
Compare and contrast the mechanisms and speed of message transmission in the nervous system versus the endocrine system.
Describe the sequence of events in a reflex arc, and how does it differ from a voluntary action in terms of the involvement of the brain?
Describe the sequence of events in a reflex arc, and how does it differ from a voluntary action in terms of the involvement of the brain?
How do sensory nerves, motor nerves, and mixed nerves differ in function, and provide an example of each?
How do sensory nerves, motor nerves, and mixed nerves differ in function, and provide an example of each?
What is the significance of the grooves and ridges on the surface of the cerebrum, and how do they contribute to brain function?
What is the significance of the grooves and ridges on the surface of the cerebrum, and how do they contribute to brain function?
Explain how effectors and receptors work together to maintain homeostasis in response to changing environmental conditions.
Explain how effectors and receptors work together to maintain homeostasis in response to changing environmental conditions.
How would damage to the cerebellum affect a person's ability to perform everyday tasks?
How would damage to the cerebellum affect a person's ability to perform everyday tasks?
Flashcards
Neuron
Neuron
Basic unit of the nervous system, consisting of cyton, axon, and dendrites.
Sensory Nerves
Sensory Nerves
Nerves that carry impulses from sense organs to the brain or spinal cord.
Motor Nerves
Motor Nerves
Nerves that carry impulses from the brain or spinal cord to muscles or glands.
Mixed Nerves
Mixed Nerves
Signup and view all the flashcards
Cranial Nerves
Cranial Nerves
Signup and view all the flashcards
Spinal Nerves
Spinal Nerves
Signup and view all the flashcards
Brain
Brain
Signup and view all the flashcards
Cerebrum
Cerebrum
Signup and view all the flashcards
Cerebellum
Cerebellum
Signup and view all the flashcards
Medulla Oblongata
Medulla Oblongata
Signup and view all the flashcards
Spinal Cord
Spinal Cord
Signup and view all the flashcards
Stimulus
Stimulus
Signup and view all the flashcards
Response
Response
Signup and view all the flashcards
Impulse
Impulse
Signup and view all the flashcards
Receptor
Receptor
Signup and view all the flashcards
Effector
Effector
Signup and view all the flashcards
Motor Neuron
Motor Neuron
Signup and view all the flashcards
Reflex Action
Reflex Action
Signup and view all the flashcards
Voluntary Actions
Voluntary Actions
Signup and view all the flashcards
Sense Organs
Sense Organs
Signup and view all the flashcards
Nerve
Nerve
Signup and view all the flashcards
Myelin Sheath
Myelin Sheath
Signup and view all the flashcards
Function of Spinal Cord
Function of Spinal Cord
Signup and view all the flashcards
Reflex Arc
Reflex Arc
Signup and view all the flashcards
Gray Matter
Gray Matter
Signup and view all the flashcards
Spinal Cord Nerves
Spinal Cord Nerves
Signup and view all the flashcards
Central Nervous System (CNS)
Central Nervous System (CNS)
Signup and view all the flashcards
Cerebral Cortex
Cerebral Cortex
Signup and view all the flashcards
Peripheral Nervous System (PNS)
Peripheral Nervous System (PNS)
Signup and view all the flashcards
Central Canal
Central Canal
Signup and view all the flashcards
White Matter
White Matter
Signup and view all the flashcards
Brain Structure
Brain Structure
Signup and view all the flashcards
Nerve Fibres
Nerve Fibres
Signup and view all the flashcards
Grooves and Ridges in the Cerebrum
Grooves and Ridges in the Cerebrum
Signup and view all the flashcards
Purpose of Sense Organs
Purpose of Sense Organs
Signup and view all the flashcards
Central Nervous System
Central Nervous System
Signup and view all the flashcards
Peripheral Nervous System
Peripheral Nervous System
Signup and view all the flashcards
Nerve Cell (Neuron)
Nerve Cell (Neuron)
Signup and view all the flashcards
What are Cranial Nerves?
What are Cranial Nerves?
Signup and view all the flashcards
What are Spinal Nerves?
What are Spinal Nerves?
Signup and view all the flashcards
What is reflex action?
What is reflex action?
Signup and view all the flashcards
What is a Reflex Arc?
What is a Reflex Arc?
Signup and view all the flashcards
What are nerves?
What are nerves?
Signup and view all the flashcards
What is the function of the myelin sheath?
What is the function of the myelin sheath?
Signup and view all the flashcards
What are Sensory Nerves?
What are Sensory Nerves?
Signup and view all the flashcards
What are Motor Neurons?
What are Motor Neurons?
Signup and view all the flashcards
What are Involuntary Actions?
What are Involuntary Actions?
Signup and view all the flashcards
What is the Brain?
What is the Brain?
Signup and view all the flashcards
What are Voluntary Actions?
What are Voluntary Actions?
Signup and view all the flashcards
What is the Medulla Oblongata?
What is the Medulla Oblongata?
Signup and view all the flashcards
What is Refractory Period?
What is Refractory Period?
Signup and view all the flashcards
What is the Cerebellum?
What is the Cerebellum?
Signup and view all the flashcards
Study Notes
Neuron Structure
- A nerve cell is the same as a neuron, which serves as the nervous system's fundamental structural and functional unit.
- A neuron comprises the cyton, axon, and dendrites.
- Nerve cells connect end to end, forming nerve fibers.
- Nerve fibers (axons) bundle within a tubular sheath, forming a nerve.
- The myelin sheath layer over the axon acts as an insulator, preventing impulse mixing between adjacent nerve fibers.
Types of Nerves
- Three nerve types exist: sensory, motor, and mixed.
- Sensory nerves transmit impulses from sense organs to the brain or spinal cord.
- Sensory nerves consist of only sensory fibers.
- The optic nerve of the eye is an example.
- Motor nerves carry impulses from the brain or spinal cord to muscles or glands.
- Motor nerves consist of only motor nerve fibers.
- Nerves to the muscles of the eyeball are an example.
- Mixed nerves carry both sensory and motor fibers.
- Nerves innervating the tongue are mixed nerves.
- Nerves are classified as cranial or spinal based on origin.
- Cranial nerves originate from the brain and reach the head region; humans have 12 pairs.
- Spinal nerves originate from the spinal cord and reach various body parts; humans have 31 pairs.
Human Nervous System
- The nervous system comprises the central nervous system (CNS) and the peripheral nervous system (PNS).
Peripheral Nervous System (PNS)
- The Peripheral Nervous System (PNS) consists of cranial nerves and spinal nerves
Central Nervous System (CNS)
- The central nervous system consists of the brain and spinal cord.
Brain
- The brain is the nervous system's main control center, protected by the cranium.
- The brain consists of the cerebrum, cerebellum, and medulla oblongata.
Cerebrum
- The cerebrum is the brain's uppermost and largest part.
- Grooves and ridges increase its surface area to accommodate numerous nerve cells.
- The cerebrum divides into right and left cerebral hemispheres.
- It controls mental activities like thinking and reasoning.
- The cerebrum is the center for intelligence and memory.
- The cerebrum is the center for perceiving pain, sound, touch, taste, and smell.
Cerebellum
- The cerebellum is located under the cerebrum at the back of the head.
- It has furrows but lacks convolutions and divides into two cerebellar hemispheres.
- The cerebellum maintains balance and coordinates muscular activities.
Medulla Oblongata
- The medulla oblongata is the brain's lowest part, linking it to the spinal cord.
- Located at the skull's base, above the spinal cord.
- The medulla oblongata controls vital involuntary activities like heartbeat and breathing.
Spinal Cord
- Extends from the medulla oblongata through the vertebral column.
- Protected by the vertebral column.
- The spinal cord has a central canal containing cerebrospinal fluid.
- Grey matter, containing neuron cell bodies, surrounds the central canal in an H-shape.
- White matter, made of nerve fibers, is the outer part.
- It conducts messages from the skin and muscles to the brain.
- It conducts commands from the brain to muscles of the body trunk and limbs.
Nervous System vs. Endocrine System
- Nervous System: Messages via nerve fibers, includes brain/spinal cord/nerves, no hormones, quick impulse transmission.
- Endocrine System: Messages via hormones in blood, includes endocrine glands, hormones secreted, slower transmission.
Basic Terms
- Stimulus: Any environmental change causing a change in body activity.
- Examples of stimuli include sound, sight, smell, pain, or touch.
- The sun is a stimulus for petals to open up (e.g., Portulaca).
- Heat is a stimulus when touching a hot plate.
- Response: Any activity resulting from a stimulus.
- Pulling a hand away from a stove is a response.
- Impulse: A wave of electrical disturbance passing through nerves.
- Receptor: Sense organs detecting stimuli and transmitting them to the CNS.
- Effector: Muscles or organs responding to a stimulus after receiving impulses from the brain or spinal cord.
Motor Neuron
- Motor neurons are in the CNS.
- Their axons project to control muscles directly or indirectly.
- Each motor neuron is multipolar, containing one axon and multiple dendrites.
- Receives information from other neurons and conveys commands to muscles.
Reflex Actions
- Living things respond to stimuli through nerves (spinal and cranial).
- Voluntary actions are controlled by the brain, such as riding a bicycle, dancing, or playing soccer.
- Reflex actions are controlled by the spinal cord, such as pulling away from a hot object.
- Reflex actions are quick, automatic, and involuntary responses to stimuli without brain involvement.
- Examples include pulling away from heat, blinking from dust, and shivering.
- Reflex arc: The path of an impulse in a reflex action.
Sequence of Events in a Reflex Action
- Heat stimulates nerve endings (receptors) in the skin.
- Impulses are produced and travel via sensory neurons to the spinal cord.
- Impulses transmit to another neuron in the spinal cord.
- Response travels from the spinal cord along the motor neuron to the effector.
- Muscles, the effector, contract, causing withdrawal.
Voluntary vs. Reflex Actions
- Voluntary Action: Controlled by the brain (cerebrum), slow response.
- Reflex Action: Involuntary, controlled by the spinal cord, very fast response.
Finger Sensitivity
- Highly sensitive fingertips contain many nerve endings for cold, heat, pain, and pressure.
Sense Organs
- Five sense organs: eyes (sight), ears (hearing), nose (smelling), tongue (taste), and skin (touch).
- Sense organs help observe and respond to changes.
- They contain receptors that receive information and transmit it to the brain via nerves.
- The brain generates a response transmitted to respective organs.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
