Nervous System Flashcards
What are the two main anatomical divisions of the nervous system?
The central nervous system (CNS) and the peripheral nervous system (PNS)
What makes up the CNS?
The brain and spinal cord
What do the brain and spinal cord contain?
Neural tissue, connective tissues, and blood vessels
What are the two main functions of the CNS?
Processing and coordinating
What are the three things the CNS processes and coordinates?
- sensory data from both inside and outside the body,
- motor commands that control the activities of peripheral organs (like skeletal muscle),
- higher functions of the brain like intelligence, memory, learning, and emotion.
What makes up the PNS?
All neural tissue outside of the brain and spinal cord
What are some structures of the PNS?
Sensors, motor neurons, and nerves
What are the functions of the PNS?
Deliver sensory info to the CNS and carry motor commands to peripheral tissue + systems
What’s the difference between afferent and efferent?
Afferent is to CNS, efferent is from CNS
What does the afferent division do?
It carries sensory info form the PNS sensory receptors to the CNS. Receptors
What does the efferent division do?
It carries motor commands from the CNS to the PNS to the effectors (muscles and glands). Effectors
What are the two divisions of the PNS?
The somatic nervous system (SNS) and the automatic nervous system (ANS)
What are the two divisions of the ANS?
The sympathetic division and the parasympathetic division
What does the SNS do?
It controls skeletal muscle contractions/ voluntary contractions
What does the ANS do?
It controls subconscious contractions/ contractions of smooth and cardiac muscle
What is the effect of the sympathetic division?
It has a stimulating effect
What is the effect of the parasympathetic division?
It has a relaxing effect
What are the two types of neural tissues?
Neurons and neuroglia
What are neurons?
They’re neural tissues that send and receive signals and and are the basic functional units of the nervous system
What are neuroglia?
They’re neural tissues that support and protect neurons
Where are neurons commonly found?
In the central nervous system (CNS)
What do neurons look like?
They have a cell body, short branched dendrites, and a long single axon
What are makes up neural tissue cells and neurons?
They have a large nucleus and nucleolus, cytoplasm, mitochondria, RER and ribosomes that make up the nissl bodies, and a cytoskeleton
What don’t neural tissue cells and neurons have?
They don’t have centrioles
What do nissl bodies do?
They produce neurotransmitters
What is a characteristic of dendrites?
They’re highly branched
What do dendrites make up?
Dendrites make up 80-90% of neuron surface area
What do dendrites do?
They receive information from other neurons
What is a characteristic of axons?
They’re long
What do axons do?
They carry electrical signals (action potentials) to the target
What different parts do axons have?
They have axon hillocks, collaterals, and synaptic terminals
What is an axon hillock?
It’s a thick section of an axon cell’s body and it attaches to the initial segment
What is a collateral?
The branches of a single axon
What are synaptic terminals?
They’re the tips of an axon, and are also known as axon terminals
What is a characteristic of bipolar neurons?
They’re small
What makes up a bipolar neuron?
One dendrite and one axon
Where are bipolar neurons found?
They’re found in special sensory organs
What are very long axons?
Unipolar neurons
What are unipolar neurons?
Very long axons
What are unipolar neurons fused to?
Dendrites and an axon
What’s a characteristic of unipolar neurons?
The cell body is to one side
Where are unipolar neurons found?
In sensory parts of the PNS
What’s a characteristic of multipolar neurons?
They have multiple dendrites and one axon
Where are multipolar neurons commonly found?
In the CNS, and it includes all skeletal muscle motor neurons
What are the three functional classifications of neurons?
Sensory neurons, motor neurons, and interneurons
What are sensory neurons?
Afferent neurons of the PNS
What are motor neurons?
Efferent neurons of the PNS
What are interneurons?
Association neurons
What are cells that support and protect neurons?
Neuroglia
What are cells that send and receive signals?
Neurons
What are the basic functional units of the nervous system?
Neurons
What carries electrical signals to the target?
Axons
What part of the axon attaches to the initial segment?
The axon hillock