Divisions of the Nervous System and the Sense
What is the nervous system's function?
It controls and coordinates functions throughout the body and responds to internal and external stimuli
What are the two main divisions of the nervous system?
the central nervous system and the peripheral nervous system
What does the central nervous system do?
it is the control center of the body; it relays messages, processes information, and analyzes information
What does the peripheral nervous system do?
It receives information from the environment and relays commands from the CNS to glands and organs
What are the main parts of the central nervous system?
The brain and the spinal cord
What is the brain protected by?
What is the spinal cord protected by?
What is the central nervous system protected by?
three layers of connective tissue called meninges that are around the spinal cord and brain
What is cerebrospinal fluid?
it bathes the brain and spinal cord and acts as a shock absorber and it also exchange of nutrients and waste products between blood and nervous tissue
Where is the cerebrospinal fluid?
it is found between the meninges and the brain/spinal cord
What is the brain?
The place to which impulses flow and from which impulses originate
How many billion neurons is the brain made out of?
What is the cerebrum?
The largest and most prominent region of the brain. It is the site of intelligence, learning, and judgement
What is the cerebrum responsible for?
voluntary activities of the body
What are the cerebral hemispheres?
a groove that separates the cerebrum into right and left hemispheres.
What connects the cerebral hemispheres?
the corpus collosum
What are the hemispheres divided into?
What are lobes named for?
the skull bones that cover them
What hemisphere controls what side of the body?
opposite; right=left, left=right
What does the right side of your brain control?
creativity and artistic ability
What does the left side of your brain control?
analytical and mathematical ability
What is the outer layer of your cerebral cortex called?
What is gray matter made of?
densely packed nerve cell bodies
What does gray matter do?
processes information from the sense organs and controls the body's movements
What is the central nervous system composed of?
the brain and spinal cord
What is the central nervous system mostly made of?
What is the peripheral nervous system composed of?
Everything but the brain and spinal cord
What is the peripheral nervous system mostly made of?
sensory and motor neurons
What is the order of how the information goes?
sensory to CNS to motor
What doesn't the brain have?
Any sensory nerves, aka, feeling
What does gray matter do?
process information from the sense organs and control the body's movements
What is the inner layer of the brain called?
What is white matter made of?
mostly axons with myelin sheaths
What does white matter do?
connects the cerebral cortex and the brain stem
How big is the cerebellum?
It is the second largest part of the brain
Where is the cerebellum?
It is located in the back of the skull
What does the cerebellum do?
It helps coordinate and balance actions of the muscles so that the body moves gracefully and efficiently
What does the brain stem do?
It connects the brain to the spinal cord
Where is the brain stem?
Under and in front of the cerebellum
What are the two main regions of the brain stem?
The medulla oblongata and the pons
What do the medulla and pons do?
help regulate blood pressure, heart rate, breathing, and swallowing
Where are the Hypo/thalamus?
Between the brain stem and cerebrum
What does the thalamus do?
receives messages from all the sensory receptors and relays it to the proper part of the cerebrum
What does the hypothalamus do?
it is the control center for recognition and analysis of hunger, thirst, fatigue, anger, and body temperature. It also controls coordination of the nervous system and endocrine system
What is the spinal cord?
the main communications link between the brain and body
How many pairs of spinal nerves are there?
What are reflexes?
quick, automatic responses to a stimulus.
What do reflexes not use?
Why do reflexes not involve the brain?
The information is processed directly in the spinal cord
What is an example of a reflex?
coughing, sneezing, blinking, DTR, and rapid response
What is the somatic nervous system?
it regulates activities that are under conscious control
What division are the somatic nervous system divided into?
sensory and motor
What does the sensory part of the somatic nervous system do?
It transmits impulses from sense organs to the CNS
What does the motor part of the somatic nervous system do?
It transmits impulses from the CNS to muscles or glands
What does the autonomic nervous system do?
regulates activities that are automatic or involuntary.
What two parts is the autonomic nervous system divided into?
sympathetic and parasympathetic
What do the sympathetic and parasympathetic do?
They work as opposites on the same organ
What are sensory receptors?
Neurons that react directly to stimuli from the environment
What are some stimuli?
light, sound, motion, chemicals, pressure, and changes in temperature
Where are the most sensory receptors?
the sensory organs
What are the five major categories of sensory receptors?
Pain receptors, thermoreceptors, mechanoreceptors, chemoreceptors, and photoreceptors
What are pain receptors?
they are all over the body except in the brain and react to chemicals released from damaged cells