CH. 3 - Functional Units of the Nervous System

Question 1

Golgi and Cajal

Answer 1

Golgi: used silver nitrate solution to help study neurons, created the “nerve net hypothesis”
Cajal: created the “neuron theory” USING the Golgi stain
1906: won a Nobel price TOGETHER

Question 2

sensory neurons, transduction, and nerve ending types

Answer 2

most simple neurons
detect and carry input to CNS.
uses transduction (converts sensory to electrical signal)
nerve endings: free, encapsulated (enhanced sensitivity), specialized (i.e. rods, cones)

Question 3

interneurons and the 3 types

Answer 3

MOST neurons are this type
carry sensory to motor, CNS function
types: stellate cells (thalamus), pyramidal cells (cortex), Purkinje cell (cerebellum)

Question 4

motor neurons

Answer 4

largest neurons
carry efferent info from the brain to spinal cord causing muscle contraction responses
within the brainstem and hindbrain.

Question 5

motor neurons: excitation vs inhibition and where it’s detected

Answer 5

all or none response (does it meet threshold?)
the AXON INITIAL SEGMENT detects whether or not the stimulus reaches this threshold, dictating whether or not a response will be produced

Question 6

neurons: cell body

Answer 6

aka soma, consists of nucleus and other organelles

Question 7

neurons: dendrites and structure that receives the info

Answer 7

increases surface area, receives afferent information, uses spines to collect incoming stimuli

Question 8

neurons: axons

Answer 8

carries efferent information to synapse
info travels down telodendria (terminal branches) to a terminal button (or end foot/axon terminal) where it reaches the PRE-SYNAPTIC membrane

Question 9

neurons: myelin and nodes of Ranvier

Answer 9

myelin: a layered sheath used to SPEED up neurotransmission by 10x
nodes: gaps in myelin where saltatory conduction occurs (jumping signal, regeneration of action potentials to carry information)

Question 10

cells of the nervous system

Answer 10

CNS: neurons
PNS: glial cells
(same function, diff. location)

Question 11

glial cells in the PNS

Answer 11

latin for glue
holds neural structures secure in place
provides support with nutrition, health, efficiency
can produce throughout lifetime

Question 12

5 types of glial cells

Answer 12

1. ependymal cell (small ovoid, secretes CSF)
2. astrocytes (heals, forms blood-brain barrier, tripartite synapse (pre/post/astro.))
3. microglial cells (derived from blood)
4. oligodendrocyte (forms myelin around neurons around the brain/spinal cord)
5. Schwann cells (forms myelin around neurons in PNS nerves)

Question 13

biochemistry: 3 subatomic particles and atomic mass

Answer 13

protons: positively charged, = atomic #
electrons: negatively charged
neutrons: no charge

Atomic mass: sum of all 3

Question 14

biochemistry: molecules vs compounds vs organic compounds

Answer 14

molecules: atoms bound by covalent bonds
compounds: two diff. elements combined at fixed ratios
organic compound: contain CARBON

Question 15

biochemistry: ions

Answer 15

electrically charged via gain or loss of an electron
cation: positive, donates (Na+, K+, Ca+)
anion: negative, loses (Cl-)

Question 16

biomolecules: 3 macromolecules + lipids

Answer 16

1. carbs (fuel)
2. proteins (function and structure)
3. nucleic acids (transmission of genes)

+ lipids

Question 17

biomolecules: protein and structure

Answer 17

monomers (train cars) make up polymers (trains) with only 20 AMINO ACIDS (like an alphabet).
polypeptide: 100-1,000 AMINO ACID chain

Question 18

biomolecules: nucleic acids

Answer 18

DNA: deoxy-, codes for genes using A&T; C&G
RNA: ribose-, codes for genes using A&U; C&G

Question 19

gene expression STEPS

Answer 19

1. starts with a DNA strand
   a. TRANSCRIPTION (switches T (thymine) to U (uracil))
2. one single strand of mRNA
   b. TRANSLATION (uses codons (3 base pairs groupings) to code for a specific AMINO ACID)
3. one polypeptide chain with amino acids derived from codons in mRNA.

Question 20

biomolecules: lipids

Answer 20

make up the PLASMA membrane
hydroPHILLIC heads are used to PROTECT the hydroPHOBIC tails on the inside.
NO POLAR SUSBSTANCES can cross
POLAR substances CAN

Question 21

crossing the plasma membrane: PASSIVE transport

Answer 21

no ATP required
diffusion: non-polar substances, WITH gradient (HIGH TO LOW)
facilitated diffusion: polar substances, requires protein aid, WITH gradient (HIGH TO LOW)

Question 22

crossing the plasma membrane: ACTIVE transport

Answer 22

uses ATP (adenosinetriphosphate energy)
AGAINST gradient (LOW TO HIGH)
non-polar and polar substances

Question 23

transmembrane transport proteins (3 types)

Answer 23

channels: always open, allow passage of specific ions (Na channel, K channel)
gated channels: allows passage of specific ions on occasion, sometimes open, sometimes closed
pumps: uses ATP to actively transport a substance across a membrane.
Na+/K+ pump: 2 K+ IN, 3 Na+ OUT