Sec 29.4 Flashcards
What does the central nervous system include?
Brain and spinal cord
What is the CNS composed of?
Interneurons
What do interneurons do?
They receive signals from sensory neurons and relay and process them within the brain and spinal cord, which then pass signals in response.
How are interneurons in the brain arranged?
Their cell bodies are clustered together (gray matter) on the outside of the brain, and their axons are clustered together (white matter) on the inside of the brain.
How are interneurons in the spinal cord arranged?
Their cell bodies are clustered together (gray matter) on the inside of the brain, and their axons are clustered together (white matter) on the outside of the brain.
What are meninges?
Three layers of connective tissue that surround and protect the brain. Between the layers are fluids that cushion the brain so that it will not bang against your skull.
What are the 3 main structures of the brain?
Cerebrum, Cerebellum, and Brainstem
What is the cerebrum?
It is the part of the brain that interprets signals from your body and forms responses (i.e. hunger, thirst, emotions, motion, and pain)
What are hemispheres? and what information do they process?
They are the right and left halves of the cerebrum. Each half processes information from the opposite side of the body.
What is the corpus callosum?
It is a thick band of nerves that connects the two hemispheres.
What happens to a signal that travels through your body and spinal cord?
When the spinal cord brings the signal from the body, it crosses over to the opposite hemisphere in the corpus callosum.
What is the cerebral cortex?
It is the outer layer of the cerebrum that interprets information from your sensory organs and generates responses.
Why is the cerebral cortex’s size deceptive?
Because it is about as thick as a pencil but its folds give it a larger surface area than expected (large enough to hold more than 10 billion neurons)
How are neurons in the cerebral cortex arranged?
They are arranged in groups that work together to perform specific tasks
How is it divided by scientists?
It is divided into 4 lobes based on function
What are the names of the 4 lobes?
Frontal lobe
Parietal lobe
Temporal lobe
Occipital lobe
What does the frontal lobe do?
controls & coordinates:
- voluntary movement
- speech production
- personality
- reasoning
- judgement
What does the parietal lobe do?
contains the sensory cortex which interprets & coordinates info about the sense of touch (multisensory information)
What does the temporal lobe do?
carries out
- speech interpretation
- hearing
- plays a role in memory
What does the occipital lobe do?
processes visual info
What makes up the inside of the cerebrum (under the cerebral cortex)?
The limbic system
Thalamus
Hypothalamus
What does the limbic system do?
It is involved in learning and emotions + includes the hippocampus and amygdala
What does the thalamus do?
It sorts information from sensory organs and passes signals between the spinal cord and other parts of the brain.
What does the hypothalamus do?
It gathers information about body temperature, hunger, and thirst and sends signals to help the body maintain homeostasis
What is the cerebellum?
It is the part of the brain that coordinates movement, maintains posture an balance, and automatically adjusts the body to move smoothly
What does the brain steam do?
It connects the brain to the spinal cord and controls the most basic activities required for life (i.e. breathing & heartbeat)
What are the three major parts of the brain stem?
Midbrain, pons, and medulla oblongata
What does the midbrain do?
It controls some reflexes (i.e. changing pupil size to control the amount of light entering the eye)
What does the pons do?
It regulates breathing and passes signals between the brain and the spinal cord.
What does the medulla oblongata do?
It connects the brain to the spinal cord and controls basic life-sustaining functions (i.e. heart function, vomiting, swallowing, and coughing.
What does the spinal column consist of?
It consists of vertebrae, fluid, meninges, and the spinal cord
What is the spinal cord?
It is a ropelike bundle of neurons that is about as wide as a thumb, and it connects the brain to the nerves found throughout the body.
Why does the brain depend on the spinal cord?
Because the spinal cord is responsible for delivering messages to the proper muscles and nerves in the PNS
What happens if the spinal cord is damaged?
Messages cannot move between the brain and the rest of the body, which results in paralysis
What are reflexes?
They are involuntary movements
What are reflex arcs?
They are nerve pathways that need to cross only two synapses before producing a response.
Why do quick reactions occur?
Because the signal never has to travel up the spinal cord to the brain
Why do reflex arcs play an important role in protecting the body from injury?
Because they intercept signals and react quickly instead of waiting for the signal of danger to travel to the brain and be interpreted then react
What does the peripheral nervous system include?
