2.4 nervous system Flashcards
(24 cards)
What are the two main classifications of the nervous system?
Central nervous system (CNS) and peripheral nervous system (PNS)
The CNS comprises the brain and spinal cord, while the PNS consists of the nerves connecting the CNS to the rest of the body.
What does the central nervous system (CNS) consist of?
Brain and spinal cord
The CNS is responsible for receiving and processing information about changes in the environment.
What types of neurons are involved in sending messages in the nervous system?
- Sensory neurons
- Motor neurons
Sensory neurons carry messages to the CNS, while motor neurons send messages away from the CNS.
How does the nervous system send messages?
As an electrical impulse along a neuron and then as a chemical message (neurotransmitters) across synapses
This dual method allows for rapid communication within the body.
What are the functions of the brainstem (medulla)?
Controls involuntary actions such as breathing, heartbeat, and blood pressure
Damage to the brainstem can be life-threatening.
What does the cerebellum control?
Balance, coordination, posture, and movement
It also plays a role in memory, attention, spatial perception, and language.
What is the largest part of the brain?
Cerebrum
It accounts for about 90% of the brain’s total volume.
What are the four primary lobes of the cerebrum?
- Frontal lobe
- Parietal lobe
- Temporal lobe
- Occipital lobe
Each lobe is associated with specific functions like problem-solving, sensory processing, and vision.
What two subdivisions make up the peripheral nervous system (PNS)?
- Somatic nervous system
- Autonomic nervous system
The PNS connects the CNS to the rest of the body.
What does the somatic nervous system control?
Voluntary actions via skeletal muscles
This includes movements like walking or picking up objects.
What does the autonomic nervous system regulate?
Involuntary actions of internal organs
This includes functions such as heart rate and digestion.
What are the two divisions of the autonomic nervous system?
- Sympathetic nervous system
- Parasympathetic nervous system
They typically have opposite effects on body functions.
What is the function of sensory neurons?
Detect changes in the environment and send messages to the CNS
They are part of the PNS.
What is the role of interneurons?
Carry impulses through the central nervous system
They are sometimes referred to as connector neurons.
What do motor neurons do?
Receive impulses from interneurons and cause a response in effectors
Effectors may include muscles or glands.
What is a synapse?
The gap between neurons
Neurotransmitters are released into the synapse to transmit messages between neurons.
How do neurotransmitters function at a synapse?
They bind to receptors on the dendrites of the next neuron
This can trigger the next neuron to convert the message into a nervous impulse.
What is the primary role of the corpus callosum?
Links the two cerebral hemispheres
It facilitates communication between the left and right sides of the brain.
What are the two types of signals used in the nervous system?
Electrical signals (nerve impulses) and chemical signals (neurotransmitters)
The nervous system utilizes both electrical and chemical means to transmit information.
What is the pathway of a stimulus in the nervous system?
Receptor, sensory neuron, interneuron, motor neuron, effector
This pathway illustrates how stimuli are processed to generate responses.
What function does noradrenaline serve in the brain?
Promotes alertness, focus, and concentration
Noradrenaline is essential for forming new memories and transferring them to long-term storage.
What is a reflex action?
An automatic response that occurs without conscious thought
Reflex actions are quick responses that may be crucial for survival.
What are the steps in a reflex arc?
- Stimulus is encountered
- Detected by a receptor
- Message sent via sensory neuron to interneuron
- Interneurons send message to motor neuron
- Motor neurons send message to effector
- Response occurs
The reflex arc allows for rapid responses to stimuli without brain involvement.
True or False: Reflex actions involve the brain in their response.
False
Reflex actions occur without the message needing to go to the brain.
