Chapter 11- Fundamentals of nervous system and nervous tissue Flashcards
Main functions of the nervous system (3)
These functions can overlap or co-occur
- Sensory input
- Integration
- Motor output (motor response)
Sensory input function
Monitors changes that occur inside the body and outside the body. We have many receptors, usually for one specific sensation
Integration function
Processing and integration of input information- the nervous system decides what response to make. The brain decides what the input means
Motor response function
Nervous system activates effector organs to cause a response. The brain or spinal cord sends a message based on the input.
Neuroglia (glial cells)
Provide support and maintenance to neurons
Neurons
Nerve cells that can respond to stimuli and transmit electrical signals. They can change membrane potential in a fraction of a second, which creates a message.
Neurons are the functional unit of the nervous system
What organs make up the central nervous system?
Brain and spinal cord
Central nervous system function
Function- is responsible for interpreting sensory input and deciding motor output
What is the peripheral nervous system composed of?
Composed of bundles of nerves coming from the brain/spinal cord
Peripheral nervous system function
Function- spinal nerves and cranial nerves link the rest of the body to the central nervous system. If a nerve is severed, that part of the body no longer exists to your brain
2 subdivisions of the peripheral nervous system
- Afferent division
2. Efferent division
Afferent division (PNS)
Carries impulses from the body to the central nervous system. Impulses allow the CNS to interpret information and send out a response.
Impulses from this division arrive at the brain
Efferent division (PNS)
Carries impulses from the CNS to the effector organs. Impulses activate muscle or glands to carry out motor response.
Impulses from this division exit the brain
Types of neuroglia (glial cells) in the CNS (4)
- Astrocytes
- Microglial cells
- Ependymal cells
- Oligodendrocytes
Types of neuroglia (glial cells) in the PNS (2)
- Satellite cells
2. Schwann cells
Astrocytes
Most abundant and versatile of the neuroglia
Star shaped, with projections connecting to and wrapping around neurons, synaptic nerve endings, and surrounding blood capillaries. Found in the CNS.
Major functions of the astrocytes (4)
- Provide a nutrient supply for neuron cells
- Makes the sure the neuron is growing in the correct direction
- Allows migration of young neurons
- “Clean up” outside neuron cells
What do astrocytes clean up outside of neuron cells?
Some substances could interfere with the function of the neurons if they’re freely floating around, such as leaked K+ ions, neurotransmitter
Microglial cells
Have long and thin processes that touch neurons, found in the CNS.
Microglial cells functions (2)
- Contact nearby neuron cells to monitor health - microglial cells pick up on neurons not doing what it’s supposed to do
- Phagocytize injured neurons
Why must microglial cells phagocytize injured neurons?
Microglial cells migrate toward injured neurons, where they transform into a macrophage and phagocytize the neuron (these neurons can’t send messages correctly, so they must be cleaned up).
Importance- the immune system has very limited access to the central nervous system
Ependymal cells
Function- lines central cavities of the central nervous system to circulate cerebrospinal fluid (CSF) within cavities. Most cells have cilia (to move and circulate CSF). Found in the CNS.
Oligodendrocytes
Associated with thicker nerve fibers in the CNS, extensions of the cells wrap around each fiber to produce a myelin sheath
Oligodendrocytes function
Create an insulating covering for individual neurons of the CNS
Importance- allows for fast and efficient transmission of electrical impulses