Nervous System Review

Neurons that have a single process extending from the cell body are classified as ____________, if they have two processes, they are classified as _________. If they have more than two processes, they are classified as __________.

unipolar, bipolar, multipolar

___________ are cells found between neurons and blood vessels

Astrocytes

Dienchaphalon

-includes hypothalamus and thalamus * thalamus- interprets all senses except smell - synapses for voluntary movement * hypothalamus- control the autonomic nervous system -coordinates the nervous and endocrine systems

What is a neuron? Label the neuron below.

-neurons are masses of nerve cells that transmit information -contain a cell body, and axon, and dendrites

Medulla oblongata

-part of the brain stem

Parietal lobe

-responsible for movement, orientation, recognition, and perception of stimuli

Occipital lobe

-responsible for visual processing

Spinal nerves are considered to be __________________ nerves, because they contain both _____________ and _____________ nerves

Mixed, sensory, motor

The nervous system consists of two parts, the brain and spinal chord make up the ____________ nervous system, and the nerves throughout the body make up the ___________ nervous system

central, peripheral

Be able to label the following membranes of the nerve: perineurium, epineurium, endoneurium, fascicle

p sure we never learned this lol it wasn't in my notes

What is a reflex? Draw a simple reflex arc and label is correctly. What responds to reflexes? What is the minimum number of synapses present in the reflex arc?

reflex- automatic response -we didn't learn about reflex arcs? -? -?

gyri

ridges

The skeletal muscles are controlled by the __________ nervous system

somatic

The junction between to communicating neurons is called the ______________

synaptic cleft

What are the four types of neuroglial cells found in the CNS? What is their function?

* CNS neuroglial cells function as support cells for the neurons 1. Microglial cells: found scattered throughout the nervous system. Least numerous and smallest neuroglia in the CNS. Function to digest debris or bacteria. Microglial cells respond to immunological alarms! 2. Oligodendrocites: wraps around the axon, forming concentric layers of cell membrane called myelin. This wrapping increases the speed at which the action potential travels along the axon. 3. Astrocytes: connect blood vessels to the neurons. They are the largest and most numerous neuroglia in the CNS. They are responsible for maintaining the blood-brain barrier, repairing damaged neural tissue, and guiding neuron development 4. Ependymal cells- form a membrane that lines the ventricles of the brain and the central canal of the spinal chord. They assist in producing, circulating, and monitoring or cerebrospinal fluid.

What are the three ways neurons are classified according to function?

* Sensory neurons- afferent neurons that make up the afferent component of the PNS -deliver information from sensory receptors to the CNS 1. Exteroreceptors- provide information about the external environment (touch, temperature, pressure, sight, smell, hearing) 2. Proprioceptors- monitor the position and movement of skeletal muscles and joints 3. Interoceptors- monitor internal environment and provide sensations of taste, deep pressure, and pain

What is a synapse? What is the purpose of the synapse? How is this purpose carried out?

* Synapse: a specialized site where the neuron communicates with another cell * purpose is to allow to neuron to communicate with another cell * carried out by releasing chemicals called neurotransmitters: - neurotransmitters are packaged in vesicles and are released by the presynaptic cell (neuron) and received by the postsynaptic cell (neuron, muscle, gland)

What are the three protective membranes that surround the brain and spinal chord?

* The meninges 1. Dura mater (tough mother)- outermost layer 2. Arachnoid mater (spider mother)- middle layer 3. Pia mater (delicate mother)- inner layer

What composes white matter versus dark matter in the brain?

* White matter- myelinated axons *Grey matter- unmyelinated axons

What is the all or none principle?

- If the neuron does not reach the critical threshold level, then no action potential will fire. -also, when the threshold level is reached, an action potential of a fixed size will always fire; for any given neuron, the size of the action potential is always the same -therefore, the neuron either does not reach the threshold or a full action potential is fired.

Brain stem

- Responsible for basic life functions such as monitoring: 1. breathing 2. heartbeat 3. blood pressure

cerebrospinal fluid

- a clear, watery liquid produced in the ventricles of the brain -produced by ependymal cells in the vertebrae -protects the spinal chord and the brain -functions: 1. protection- cushions blows to the brain 2. buoyancy- because the brain is immersed in fluid, its net weight decreases 3. removal of wastes- the one way flow from the CSF to the blood takes potentially harmful metabolites, drugs, and other substances away from the brain 4. endocrine medium for the brain- the CSF serves to transport hormones to other areas of the brain

What is an action potential?

- an electrical impulse or signal passed from one neuron to another

Cerebrum

- associated with higher brain functions such as thought and action - divided into four lobes: 1. frontal lobe- reasoning, problem solving, speech, emotions, movement 2. Parietal- movement, orientation, recognition, perception of stimuli 3. Occipital- visual processing 4. Temporal- auditory processing, memory, speech

cerebellum

- associated with regulation and coordination of movement, posture, and balance

What is the corpus callosum?

- bundle of axons which connects the two hemispheres

Spinal chord

- bundle of neurons, about 17" in length - made of two types of tissue: 1. grey matter (inner layer): made of nerve cell bodies, neuroglial cells, and blood vessels 2. white matter (outer layer): made of axons -consists of 31 segments. each segment gives rise to a pair of spinal nerves -conducts nerve impulses -serves as a center for spinal reflexes

Temporal lobe

- responsible for auditory processing, memory, speech

Frontal lobe

- responsible for reasoning, problem solving, speech, emotions, and movement

What do each hemisphere control?

- right: creativity - left: logic and reasoning

What is the purpose of the folds of the brain?

- they increase the surface area

What are the two functional divisions of the PNS?

1. Afferent division- brings sensory information to the CNS from receptors in peripheral tissues and organs 2. Efferent division- carries motor commands from the CNS to the muscles and glands -target organs that respond by doing something are called effectors

What are the four ways that neurons are classified according to structure?

1. Anaxonic neuron- have no distinct processes -located in the brain and special sense organs -function is poorly understood 2. Bipolar neurons- have two distinct processes, one dendrite and one axon with cell body between them -rare, but found in special sense organs where they relay information about sight, smell, or hearing from receptor cells to neurons 3. Unipolar neuron- dendrites and axons are fused together and continuous, cell body lays off to one side -most sensory neurons of the PNS are unipolar -very long (a meter or more), longest extend from the tips of toes to the spinal chord 4. Multipolar neuron- two or more dendrites and one axon -most common type of neuron in the CNS -can also be very long

How can the nervous system be divided? What is included in each system?

1. Central nervous system- brain and spinal chord 2. Peripheral nervous system- nerves (31 pairs of spinal nerves and 12 pairs of cranial nerves)

What is the function of each division of the nervous system?

1. Central nervous system- responsible for integrating, processing, and coordinating sensory data and motor commands *sensory data: conveys information about conditions inside or outside of your body * motor commands: control or adjust the activities of peripheral organs, like the skeletal muscles 2. Peripheral nervous system: delivers sensory information to the CNS and carries motor commands to peripheral tissues and systems

What four things protect the brain?

1. Meninges 2. Skull 3. Cerebrospinal fluid 4. Blood-brain barrier

Describe the steps of an action potential.

1. Neuron is at resting potential (-70 mV) 2. Neurotransmitters bind to receptors on dendrites 3. Causes Na+ to rush into the cell body 4. Membrane potential becomes more positive (+30 mV) 5. Na+ channels close 6. K+ rushes out of the cell to balance out differences in membrane potential 7. Membrane potential goes to -100 mV but then goes back to -70 mV 8. Continues along length of axon 9. Action potential reaches axon terminal and Ca+2 channels open 10. Ca+2 enters axon terminal and binds to vesicles 11. Vesicles with neurotransmitters inside travel to end of axon terminal 12. Vesicles release neurotransmitters into synaptic cleft 13. Neurotransmitters travel through synaptic cleft and bind to next neuron

What are the two types of neuroglial cells found in the PNS? What is their function?

1. Satellite cells (amphicytes)- regulate the environment around the neurons, similar to astrocyte's job 2. Schwann cells- myelinates only one segment of a single axon. Also engulfs damaged and dying nerve cells.

What are the three basic functions of the nervous system?

1. Sensory- gathers information 2. Integrative- information is brought together 3. Motor- responds to signals to maintain homeostasis

What two systems to the efferent system of the PNS break down into?

1. Somatic nervous system- controls skeletal muscle contractions (voluntary) and involuntary skeletal contractions like those seen in reflexes (automatic response) 2. Autonomic nervous system- provides automatic regulation of smooth muscles, cardiac muscle, and glands (involuntary)

The smooth muscles and glands are controlled by the ___________ nervous system

Autonomic

fissures

deep grooves

Neurons consist of a cell body, axons, and ____________, which receive information

dendrites

sulci

grooves

White matter is composed of axons that are sheathed in __________

myelin