Nervous System Flashcards
What is the Central Nervous System composed of?
Brain and Spinal Cord
What is the Peripheral Nervous System composed of?
Nervous structures outside the CNS (nerves and ganglia)
What are the subdivisions of the PNS?
PNS
–> Somatic nervous system (voluntary)
–> Autonomic nervous system (involuntary)
- Sympathetic (fight or flight)
- Parasympathetic (rest and digest)
What is the role of the autonomic nervous system?
Autonomic sensory neurons and autonomic motor neurons convey information from the CNS to smooth muscle, cardiac muscle and glands. (regulates the activity of cardiac muscles, smooth muscle and glands)
What is the role of the somatic nervous system?
Somatic sensory neurons and somatic motor neurons (voluntary) convey information to and from the CNS to and from skeletal muscles.
What is the role of neurons?
Neurons are able to generate electrical impulses in response to stimuli.
What are sensory neurons?
Sensory nears pick up information in the periphery and relay it back to the spinal cord and the brain.
What are motor neurons?
Motor neurons relay information away from the brain and spinal cord out to the periphery (to glands and muscle cells).
Draw a motor neuron.
Draw a sensory neuron.
What are glial cells?
Glial cells help to protect and maintain healthy function of neurons.
E.g. insulation of neurons (myelin) so that electrical signals can travel more quickly.
CNS - e.g. Astrocytes, oligodendrocytes, microglia
PNS - e.g. Schwann cells
What is / what is the role of myelination?
Myelin is formed by glial cells wrapping themselves around the axon of a nerve cell. PNS - Schwann cells, CNS - oligodendrocyte.
Myelin insulates the cell membrane of the nerve cell against flow of electrical current - preventing formation of action potentials. Myelination increases the speed of electrical communication down the length of the axon.
What are the types of neurons / draw a picture?
- Multipolar neuron (located in the brain and spinal cord)
- Bipolar neuron (located in the retina, inner ear and olfactory area)
- Unipolar neuron (sensory receptors for touch, pressure, pain, temperature)
Draw and explain neurotransmitters and the synapse?
What cavities are the brain and spinal cord (CNS) enclosed within?
The cranial cavity and the vertebral cavity.
What are the two basic types of nervous tissue within the CNS?
Gray matter (cell bodies of neutrons), and white matter (contains the myelinated axons of neutrons.
A single neuron can extend into regions of both gray matter and white matter in the CNS.
What does gray matter form?
The surface layer of the cerebrum (the cerebral cortex) and the inside of the spinal cord.
What is the brain made up of?
- Cerebrum (two hemispheres)
- Diencephalon (thalamus and hypothalamus)
- Brainstem (midbrain, pons and medulla oblongata)
- Cerebellum
How is the cerebrum divided?
Divided into two hemispheres (left and right). Created by a deep narrow groover that partly separates the cerebral hemispheres (called the longitudinal fissure). Cerebral hemispheres are also interconnected by white matter (nerve fibre) (called the corpus callosum).
Describe the outer surface of the cerebral hemisphere.
The outer surface of the cerebral hemisphere consists of a thin film of gray matter (cerebral cortex), which is several millimetres thick and consists mostly of neuron cell bodies, non-myelinated axons and dendrites arranged in different layers, plus supporting neuroglia.
The surface of the cerebrum is highly folded into gyri which allow a greater amount of cortex to fit into the cranial cavity. Prominent grooves (sulci), divide the cerebrum into distant lobes. Four of these lobes are visible superficially and the fifth sits deep to the lateral sulcus. White matter consists of militated axons and forms the bulk of the cerebral hemispheres.
What is the diencephalon?
A structure deep within the brain that forms the walls of the third ventricle (hollow space within the brain).
Consists of:
1. Thalamus (conducts various sensory processing, i.e. processes sensory input on its way to cortex)
2. Hypothalamus (controls various homeostatic functions)
What makes up the brainstem?
Midbrain, pons and medulla oblongata.
What is the role of the brainstem?
The brainstem connects the diencephalon to the spinal cord and is where most cranial nerves originate. Also is the site of cardiovascular, respiratory and digestive centres.
What is the role of the cerebellum?
The cerebellum helps coordinate muscular activity and maintain posture. It forms the posterior wall of the fourth ventricle and is connected to the brainstem.
