Human Physiology Exam 2

Type A nerve fibers

large-diameter, myelinated. Motor neurons supplying skeletal and most sensory neurons

Type B Nerve Fiber

myelinated, cutaneous and subcutaneous mechanoreceptors

Type C Nerve Fiber

smallest diameter, unmyelinated-slowest

Synapse

A junction where information is transmitted from one neuron to the next.

What are the 2 types of synapses?

excitatory - up and down neuron firing rate same

inhibitory- up and down neuron firing rate is alternative

What produce EPSPs or IPSPs?

Neurotransmitters

What do not produce EPSPs or IPSPs?

Neuropeptides

What are small molecules (amino acids)?

Neurotransmitters

What are large molecules (2-40 AA)

Neuropeptides

What act quickly and are destroyed quickly?

Neurotransmitters

What act slowly and have a prolonged response?

Neuropeptides

What are synthesized locally?

Neurotransmitters

What are synthesized in the cell body?

Neuropeptides

What act to open LGICm others use 2nd messenger systems in the post- synaptic neuron only?

Neurotransmitters

What mostly use 2nd messenger systems, can act either pre- or post-synaptically?

Neuropeptides

What type of neuron sends signals towards the CNS (central nervous system)?

Afferent neuron

What neuron has long axon in the PNS (peripheral nervous system)?

Afferent & Efferent neuron

What neuron generates action potentials (AP) from sensory receptors?

Afferent neuron

What neuron is found entirely within the CNS (central nervous system)?

Interneurons

What neuron lies between afferent & efferent neurons?

Interneurons

What neuron sends signals away from the CNS (central nervous system) to effector organs (muscle/glands)

Efferent Neurons

What is maintained information about stimulus and is valuable, does not adapt or adapts very slowly?

Tonic

What adapts rapidly but generate an off response on removing the stimulus?

Phasic

The change in stimulus intensity is important in what phase?

Phasic

True or False: Stimuli of the same intensity do produce the same magnitude of receptor potentials from the same receptor

FALSE

What does the First order of the transmission of stimulus do?

Transmit sensor information from the periphery to the CNS (central nervous system)

What does second order of the transmission of stimulus do?

Communicate with reflex networks in spinal cord & travel to thalamus

EX: touching a hot tea pot : hand retracts with the sensory it is hot

What does third order of the transmission of stimulus do?

Relay information from thalamus to cerebral cortex

Glial cells

cells in the nervous system that support, nourish, and protect neurons

What do microglia do?

they act as immune defenders, scavengers and secrete NGF (Nerve Growth Factor)

What do Ependymal cells do?

they produce & forms CSF (cerebrospinal fluid), and serve as neural stem cells

What do oligodendrocytes do?

form myelin sheaths in the Central Nervous System

If oligodendrocytes are not formed what happens?

The body experiences demyelination which means the nerve fibers in the CNS are lacking the insulating of myelin sheath. This can result in difficulties in movement, vision, cognition and sensory perception.

What are functions of the Frontal lobe?

1. voluntary Motor activity

2. Speaking Ability (left only)

3. Higher order functions

What are functions of the Parietal lobe?

Receiving and processing of sensory input, language comprehension

What are functions of the temporal lobe?

hearing and smell

What does the occipital lobe do?

visual processing

What are some of the functions of the Cerebral cortex?

1. Sensory

2. Voluntary control of movement

3. Language

4. Personality traits

What are some of the functions of the Basal Nuclei?

1. Inhibition of muscle tone

2. Coordination of slow, sustained movements

3. Suppression of useless patterns of movement

What are some of the functions of the thalamus?

1. Relay station for all synaptic input

2. Crude awareness of sensation

3. Some degree of consciousness

4. Role in motor control

What are some functions of the Hypothalamus?

1. Regulation of many homeostatic functions (temperature control, thrust, urine output and food intake)

2. Important link between nervous and endocrine system

3. Role in sleep - wake cycle

What are functions for the cerebellum?

1. Balance

2. Enhancement of muscle tone

3. Coordination and planning of skilled voluntary muscle activity

What are functions of the brain stem?

1. Origin of majority of peripheral cranial nerves

2. Regulation of muscle reflexes involved with equilibrium, and posture