Nervous system -- Lecture 20 Flashcards
genes in development:
homeotic genes (definition)
genes which are critical for making sure anatomical structure developing the correct # and in the correct locations
genes in development:
mutations in homeotic genes:
lead to the appearance of body parts in inappropriate places
and/or
the wrong # of particular body parts
homeotic genes:
bithorax genesdffg (what is it and what does it result in?)
mutation results in a duplication of the section of thorax that gives rise to the wings
results in a fly w/ 2 complete sets of wings
what is morphogenesis in development?
development and final shaping of specific anatomical structures
morphogenesis in development:
morphogenesis results from changes in:
cell growth and differentiation
cell shape
cell migration
cell death
cell death in morphogenesis:
apoptosis (definition)
programmed cells earth is a part of development
cell death in morphogenesis:
example of apoptosis in human embryos
developing human embryos begin w/ webbed fingers and toes
during development, cells that make up the webbing go thru apoptosis
failure of morphogenesis:
example of failure of morphogenesis in humans:
syndactyly: failure of the tissue b/n 1 or more fingers or toes to got thru apoptosis
nervous system:
what are the 3 functions?
interprets information about the body
interprets information about the environment
decides whether and how to respond
nervous system:
how many subdivisions are there?
2
nervous system:
what are the 2 subdivisions of the nervous system?
central nervous system (CNS)
peripheral nervous system (PNS)
nervous system:
what does the central nervous system (CNS) consist of?
brain, spinal cord, and interneurouns w/in the brain and spinal cord
nervous system:
what does the peripheral nervous system (PNS) consist of?
consists of sensory neurons and motor neurons
nervous system:
pathway of how the CNS and PNS work together
sensory neurons (PNS) –> interneurons (CNS) –> brain process (CNS) –> interneurons (CNS) –> motor neurons (PNS)
types of neurons:
vertebrates have ___ types of neurons
3
types of neurons:
___ have 3 types of neurons
vertebrates
types of neurons:
what are the 3 types of vertebrate neurons?
1) sensory neurons (PNS) – carry info about the body and environment to the CNS
2) interneurons (CNS) – provide a link b/n the sensory neurons, brain, and motor neurons
3) motor neurons (PNS) – carry impulses from CNS to effectors (muscles and glands)
neuron (nerve cell) structure:
dendrites (what do they do)
receive signals (using receptors) and send electrical pulses (action potentials) to the cell body
neuron (nerve cell) structure:
what is the action potential?
what direction does it travel?
electrical impulse carrying signal
travels from dendrite, across axon, to axon terminal
neuron (nerve cell) structure:
cell body (what is it and what does it do)
consists of the nucleus sea do the metabolic machinery
can transmit the action potential to the axon
neuron structure:
axon (what does it do)
conducts the action potential to the axon terminals (end)
neuron structure:
axon terminals (what do they do)
a transmit the signal thru a synapse to the next cell
neuron structure:
myelin sheath (what is it)
discontinuous covering around the axon, formed by layers of Schwann cells
neuron structure:
nodes of Ranview (what are they)
gaps in the myelin sheath
neuron structure:
Schwann cells (what are they)
cells that form layers to form the myelin sheath
neuron structure:
myelin sheath (what does it do)
speeds the transmission action potentials down the axon
damage to the ___ is behind several diseases
myelin sheath
damage to the myelin sheath is behind several diseases:
multiple sclerosis (what is it)
disease in which the immune system destroys the myelin sheath
nerve signaling becomes slow and inefficient
causes coordination and walking problems, numbness, and vision problems
damage to the myelin sheath is behind several diseases:
charcot-marie-tooth (CMT) syndrome (what is it)
group of inherited genetic disorders that can cause damage to the myelin sheath
causing muscle weakness, loss of sensation, and muscle atrophy
the ___ nervous system interprets information gathered by sensory neurons
central
