Chapter 1 The Nervous System Flashcards
The three components of the nervous system.
the brain, spinal cord and peripheral nervous
Two kinds of cells in the nervous system.
neurons and glial cells
Three kinds of neurons.
sensory neurons, motor neurons, and interneurons
The function of sensory neurons.
detect the different attributes of the internal and external environment
The function of motor neurons.
control the activity of muscles, are responsible for all forms of behavior
The function of interneurons.
mediate simple reflexes as well as being responsible for the highest functions of the brain
The function of glial cells.
have a purely supporting function to the neurons
The structure of neurons.
consist of a cell body and two sets of additional compartments called processes.
Axons
one of the sets, the job is to transmit information from the neuron on to others to which it is connected.
Dendrites
the other set, the job is to receive the information being transmitted by the axons of other neurons.
Synapses
the specialized contacts which both of the processes participate in
How do neurons organize?
Neurons are organized into complex chains and networks that are pathways through which information in the nervous system is transmitted.
What are the brain and spinal cord connected to?
The brain and spinal cord are connected to sensory receptors and muscles through long axons that make up the peripheral nerves.
Two functions of the spinal cord.
- It is the seat of simple reflexes such as the knee jerk and the rapid withdrawal of a limb from a hot object or a pinprick, as well as more complex reflexes.
- It forms a highway between the body and the brain for information travelling in both directions.
How is the human brain distinguished?
By its large size in relation to body size. This is due to the enormous increase in the number of interneurons over the course of evolution, providing humans with an immeasurably wide choice of reactions to the environment.
Two main components of the brain.
The brain stem and the cerebral hemisphere.
Three main components of the brain stem.
hind-brain, mid-brian, and diencephalon.
The hind-brain
an extension of the spinal cord, which contains networks of neurons that constitute centers for the control of vital functions such as breathing and blood pressure.
Cerebellum
arising from the roof of the hind-brain, which plays an absolutely central role in the control and timing of movements.
Mid-brain
contains groups of neurons, each of which seems to use predominantly a particular type of chemical messenger, but all of which project up to cerebral hemispheres.
Two components of the diencephalon
the thalamus and the hypothalamus
Thalamus
relays impulses from all sensory systems to the cerebral cortex, which in turn sends messages back to the thalamus.
Hypothalamus
controls function such as eating and drinking, and it also regulates the release of hormones involved in sexual functions
components of the cerebral hemisphere
a core called the basal ganglia and an extensive but thin surrounding sheet of neurons making up the grey matter of the cerebral cortex
