Questions and Answers
Which of the following is an example of a spinal reflex?
Cerebral reflexes are formed from the spinal cord.
False
What part of the nervous system controls activities beyond our conscious awareness?
Autonomous nervous system
The pathway of impulses in a reflex action is known as the __________.
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Match the following parts of the reflex arc with their functions:
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What is the primary component of the outer part of the spinal cord?
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Motor impulses enter the spinal cord through the dorsal root.
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What are the protective membranes surrounding the spinal cord called?
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The spinal cord connects to the body through _____ pairs of spinal nerves.
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What is the space between the meninges and the central canal filled with?
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Match the following functions with their descriptions:
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Reflex actions require conscious thought to occur.
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What happens during a spinal reflex when the leg steps on something hot?
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Which part of the nervous system includes the cranial and spinal nerves?
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The cerebrospinal fluid is produced by the brain and is never reabsorbed into the blood.
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What is the protective membrane that covers the brain called?
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The nervous system consists of the ________ and the peripheral nervous system.
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What type of nerve carries impulses from the brain and spinal cord to various parts of the body?
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Match the following components of the nervous system with their characteristics:
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The brain is protected by a single-layered membrane.
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The ________ system of the peripheral nervous system is responsible for the 'fight or flight' response.
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What is the response of the pupil in the eye under the sympathetic system?
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During an emergency situation, the parasympathetic system increases production of saliva.
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What happens to the heart rate in the sympathetic system during an emergency?
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The condition characterized by an accumulation of an insoluble protein in the neural tissues of the brain is known as _____ disease.
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Match the following organs with their response during the sympathetic system:
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Which of the following statements is true regarding the parasympathetic system?
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The parasympathetic system causes peristalsis in the intestine to slow down.
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What is the main reason for a healthy nervous system according to the content?
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What is the primary function of a neuron's axon?
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Receptors can only respond to internal stimuli.
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What are the two types of stimuli?
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The ___ is the structural and functional unit of the nervous system.
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Match the parts of a neuron with their respective functions:
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What part of the neuron carries impulses to the synaptic knob?
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The nervous system includes only the brain and spinal cord.
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What are specialized cells that receive stimuli called?
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Study Notes
Stimulus and Responses
- Stimuli are sensory inputs that elicit responses in organisms.
- External stimuli include environmental factors such as heat, cold, touch, and sound.
- Internal stimuli arise from within the organism, e.g., hunger and thirst.
Receptors
- Specialized cells located in sense organs that detect stimuli are known as receptors.
- Receptors convert stimuli into impulses, such as photoreceptors in the eyes and taste receptors on the tongue.
Responses
- Responses are initiated when impulses generated by receptors are transmitted to the brain.
Nervous System Overview
- The nervous system regulates and coordinates bodily functions.
- Composed of the brain, spinal cord, nerves, and receptors.
- Neurons are the fundamental units of the nervous system.
Neuron Structure
- Neurons have a cell membrane, cytoplasm, and nucleus.
- Key components include:
- Dendron: Carries impulses from dendrites to the cell body.
- Dendrite: Receives impulses from adjacent neurons.
- Axon: Longest filament that transmits impulses from the cell body.
- Axonite: Branches from the axon that lead to synaptic knobs.
- Synaptic Knob: Releases neurotransmitters.
Types of Nerve Fibers
- Motor Nerves: Transmit impulses from the brain/spinal cord to body parts.
- Mixed Nerves: Contain both sensory and motor fibers.
Nervous System Classification
- Divided into:
- Central Nervous System (CNS): Includes the brain and spinal cord.
- Peripheral Nervous System (PNS): Comprised of cranial and spinal nerves, plus the autonomic nervous system.
Brain Protection
- The brain is encased in the skull and covered by protective membranes called meninges.
- Cerebrospinal fluid (CSF) surrounds the brain, maintaining pressure, providing nutrients, and offering protection.
Spinal Cord
- A tubular structure safeguarded within the vertebral column, it extends from the medulla oblongata.
- Composed of:
- White matter on the outside.
- Grey matter on the inside containing a central canal.
Spinal Nerves
- Formed by merging nerve fibers from dorsal (sensory) and ventral (motor) roots.
- Dorsal roots carry sensory impulses; ventral roots carry motor impulses.
Spinal Cord Functions
- Transmits impulses between the body and brain.
- Coordinates repetitive movements like walking.
- Initiates reflex actions.
Reflex Actions
- Involuntary responses to stimuli are termed reflex actions.
- Examples include withdrawal from pain and blinking when an object approaches the eye.
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Reflex Arcs consist of:
- Receptor (detects stimulus).
- Sensory neuron (sends impulses to the CNS).
- Interneuron (connects sensory and motor neurons).
- Motor neuron (carries commands to effectors).
- Effector (carries out the response).
Autonomic Nervous System (ANS)
- Regulates involuntary functions, divided into sympathetic and parasympathetic systems.
Sympathetic vs. Parasympathetic Responses
- Sympathetic responses prepare the body for emergency (e.g., pupil dilation, increased heart rate).
- Parasympathetic responses promote restful states (e.g., pupil constriction, reduced heart rate).
Importance of a Healthy Nervous System
- Essential for rhythmic body activities; minor issues can disrupt physiological functions.
Nervous System Diseases
-
Alzheimer’s Disease:
- Caused by protein accumulation in the brain leading to neuron destruction.
- Symptoms include memory loss and disorientation in social situations.
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Description
Explore the fundamentals of sensations and responses in this biology quiz. This chapter covers concepts such as stimuli, receptors, and how organisms react to both external and internal stimuli. Test your knowledge on the mechanisms of sensory perception!