BIOL 319 Lab 8

learned reflexes example

driving a car

inborn reflex example

breathing, maintain posture, and avoid pain

reflex arcs 5 parts

1. receptor that senses the stimulus and initiates the signal 2. sensory neuron that carries afferent nerve impulses to the central nervous system 3. integration center where signal is processed 4. motor neuron that carries efferent signals to effector from integration center 5. effector such as muscle or gland which generates a response to the signal

monosynaptic reflex

single synapse between a motor and sensory neuron serves as integration center

polysynaptic reflex

integration center will include a few synapses and interneurons

what is the integration center for most reflexes

central nervous system

somatic reflex

activates skeletal muscle

autonomic reflex

controls visceral effectors such as smooth muscle, cardiac muscle, or a gland

proprioceptors examples

tendon organs and muscle spindles

proprioceptors

supply information to central nervous system about bodies position in space and how much a muscle has moved or not moved

all stretch reflexes are

ipsilateral and monosynaptic

stretch reflex

stimulates muscle contraction when muscle length is increase or the muscle is stretched

tendon reflex

causes muscles to relax in circumstances of high tendon tension

direct light or pupillary reflex

involves four neurons that connect retina to mid-brain and then convey information back to pupillary sphincator muscles

consensual light reflex

the constriction of one pupillary sphinctor muscle causes the other pupillary sphinctor muscle to constrict

mydriasis

pupillary dilation

Babinskis sign

instead of toes flexing, the great toe dorsiflexes and the other toes laterally fan

plantar reflex

running blunt object down lateral sole of foot at toes should flex

glial cells

play a role in protecting and maintaining nervous tissue

neurons

communication cells

neuroglia

network made up of glial cells

central nervous system glial cells

astrocytes, microglia, ependymal cells, and oligodendrocytes

peripheral nervous system glial cells

satellite cells and schwann cells

astrocytes

most abundant and versatile glial cell and guide migration of young neurons

microglia

monitor nearby neurons health and migrate toward injured neurons

ependymal cell

line central cavities of brain and spinal cord, cilia help circulate fluid

oligodendrocyte

produce insulating coverings called myelin sheaths

satellite cells

surround neuron cell bodies

Schwan cells

vital to regeneration, and increase speed of nerve impulses

neurons consist of

dendrites, axons and a cell body

dendrites

main receptors/input regions and convey messages toward cell body called graded potentials

axons

transmits signals from cell body to other neurons

cell body (soma)

surrounds nucleus

nissl bodies

Rough ER granules in the soma

nuclei

clusters of soma in CNS

ganglia

clusters of soma in the PNS

myelinated fibers

conduct nerve impulses rapidly