Exam 2 Vocab Flashcards
(129 cards)
1
Q
Choline Acetyl Transferase
A
Enzyme that combines Acetyl CoA and Choline to make ACh
2
Q
Schwann Cells and Oligodendrocyte
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Form myelin sheaths in the PNS and CNS, respectively
3
Q
Nodes of Ranvier
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Portions of the axon not covered by myelin sheaths. saltatory conduction.
Results in saltatory conduction: Instead of slowly walking the length of the axon, AP jumps from node to node
4
Q
Neurotrophins
A
In fetal brain: Promote Neural Growth
In Adults: Aid in maintenance and recovery of neural cells
5
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Astrocytes
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Influence production of ion channels and enzymes that can destroy toxic substances by secreting glial-derived neurotrophic factor
6
Q
Absolute Refractory Period
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Period when you CANNOT have another AP
7
Q
Relative Refractory Period
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Period of rest, when you CAN have another AP, if the stimulus is strong enough (though it is not likely)
8
Q
Presynaptic Cell
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Transmits Signal
9
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Postsynaptic Cell
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Receives Signal
10
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Connexins
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Proteins that form gap junctions in cells (i.e. intercalated discs in cardiac muscle)
11
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Synaptotagmin
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Ca sensor in presynaptic cells that causes exocytosis of synaptic vesicles
12
Q
Nuclei (not as in, nucleus, plural)
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Clusters of cell bodies In the CNS
13
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Ganglia
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Clusters of cell bodies in the PNS
14
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Tract
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Bundles of axons in the CNS
15
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Nerves
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Bundles of axons in the PNS
16
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Excitatory postsynaptic potentials (EPSP’s)
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Neurotransmitters cause depolarization events, opening Na+ and Ca+ channels (in)
17
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Inhibitory postsynaptic potentials (IPSP’s)
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Neurotransmitters cause depolarization events, opening Cl- channels (in) and K+ channels (out)
18
Q
Acetylcholine
A
- Parasympathetic
- When it binds to receptors, it opens ion channels
- Decreases heart rate
- It can be inhibitory or excitatory depending on what it’s binding to
19
Q
AChE
A
Regulates ACh in the synapse. Breaks down ACh into acetate and choline. Choline is taken back into the cell to make more ACh later
20
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Nicotinic Receptors
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- Inotropic
- Receptors are the channels
- Rapid response in cells
- Neuromuscular junctions, ganglionic neurons, adrenal medulla
21
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Muscarinic Receptors
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- Work by being associated with G proteins
- GPCR (G protein coupled receptor)
- Metabotropic
- Slow response, because the receptor is not the channel. A bunch of other stuff has to happen within the cell in order for the channel to open
- CNS, pm of smooth and cardiac muscle, and glands
22
Q
Agonists
A
Drugs that will stimulate a receptor (i.e. nicotine and muscarine)
23
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Antagonists
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Drugs that will inhibit a receptor (i.e. atropine and curare)
24
Q
Monamine Oxidase (MAO)
A
Degrades monoamines in the presynaptic cell and will activate GPCR’s with cAMP as a second messenger
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Ionotropic Receptor
No second messenger, fast acting, receptor is the channel etc.
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Metabotropic Receptor
Second messenger system, slower acting, uses G proteins
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Meninges
Protective covering around the brain, kinda like shrink wrap
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Gyrus
Folds
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Sulcus
Creases
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3 Main Regions
Prosencephalon (forebrain); Mesencephalon (midbrain); Rhombencephalon (hindbrain)
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Ventricles
Contain CSF (cerebral spinal fluid)
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Prosencephalon
Telencephalon and Diencephalon
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Mesencephalon
Mesencephalon
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Rhombencephalon
Mesencephalon and Myelencephalon
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Contralateral Hemispheres
Left controls right, and right controls left
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Telencephalon (forebrain)
Cerebrum. Responsible for higher mental functions
Left: Language, speech, writing, calculations, and understanding music
Right: Visual-spatial tasks, facial recognition, composing music, reading maps
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Frontal Lobe (forebrain)
Voluntary motor control of skeletal muscles, personality, higher intellectual processes, verbal communication
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Parietal Lobe (forebrain)
A lot of language stuff and...
Somatesthetic interpretation (touch senses), understanding speech and formulating words to express thoughts and emotions, interpretations of textures and shapes
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Occipital Lobe (forebrain)
A lot of vision stuff and...
Interpretation of movements in focusing the eye, correlation of visual images with previous visual experiences and other sensory stimuli, conscious perception of vision
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Temporal Lobe (forebrain)
A lot of hearing stuff and...
Interpretation of auditory sensations; storage (memory) of auditory and visual experiences
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Insula (forebrain)
Memory; sensory (principally pain) and visceral integration
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Broca's area (forebrain)
Motor speech
Broca's area aphasia. Brocas area not working... So people with this are hesitant to speak, because they can't control their mouths well or articulate words well
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Wernicke's area (forebrain)
Language comprehension
Wernicke's area aphasia: No trouble talking, but they don't make sense.
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Precentral Gyrus (forebrain)
Motor cortex
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Central Sulcus (forebrain)
Physical division between frontal and parietal lobes
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Limbic System (Emotional Brain)
Controls aggression, fear, feeding, sex, goal-directed behaviors
Composed of: Amygdala, hippocampus, hypothalamus are all central components of the limbic system
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Memory
Main Areas: temporal lobe, hippocampus, amygdala (fear responses), prefrontal cortex (short term memory), left inferior frontal lobe (math)
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Long Term Memory
Requires gene activation, protein production, formation of new synapses
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Alzheimer's Disease
Caused by the formation of extracellular amyloid beta and the accumulation of Tau protein
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Diencephalon (forebrain)
Consists of the epithalamus, thalamus, hypothalamus and part of the pituitary gland
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Thalamus (forebrain, diencephalon)
Filters out background noise and sensory information.
| Relay center for all sensory information except for smell
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Epithalamus (forebrain, diencephalon)
Contains pineal complex --> circadian rhythms and melatonin secretion (helps you sleep)
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Hypothalamus (forebrain, diencephalon)
- Main job is regulating homeostasis (body temp, hunger etc.)
- Part of the limbic system
- Contains center for emotions (limbic stuff)
- Master control gland of the endocrine system
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Mesencephalon (midbrain)
Superior colliculi (reflex optical responses)
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Metencephalon (hindbrain)
Cerebellum and pons
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Myelencephalon (hindbrain)
Medulla oblongata
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Cerebellum (hindbrain, metencephalon)
- 2nd largest brain structure
- Outside is gray, inside is white
- Responsible for motor coordination, and aquisition of sensory data, memory, and emotion
- Alcohol effects the cerebellum
- Only 10% of brain weight, but it has as many neurons as the rest of the brain combined
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Pons (hindbrain, metencephalon)
Controls alertness, dream states and sleep cycles
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Medulla Oblongata (hindbrain, myelecephalon)
- Reflex centers for breathing, basal vasodilation, and heart rate
- If it is damages, you probably aren't going to survive
- Pathways for communication betweens spinal cord and brain
- Located right above spinal cord
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Varicosities
- Swellings within the axon that release neurotransmitters along the way.
- Synapses en passant: "in passing"
- Often have antagonistic effects between PS and S
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Preganglionic
From CNS to PNS
| Always release ACh
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Postganglionic
From PNS
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Sympathetic Division (ANS)
Increases heart rate; Fight or flight, digestive activity decreases
postganglionic cells will be longer, preganglionic cells will be shorter
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Parasympathetic
Decrease heart rate; Rest and digest. Digestive activity increases
preganglionic neurons will be longer, postganglionic neurons will be shorter
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Preganglionic cell body location
S: thoracic and lumber regions of the spinal cord
PS: hindbrain and sacral region of the spinal cord
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Ganglia location
S: Chain that runs close to the spinal cord
PS: Close to the effector (target organ, smooth muscle or glands)
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Number of postganglionic neurons that synapse with a single preganglionic neuron
S: 10 or more (want a faster response. A need to increase oxygen levels and blood flow very quickly)
PS: Three or less (not as much of a need for a fast response, not as many connections)
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Adrenergic Stimulation
Stimulated by epinephrine or norepinephrine (S)
| Stimulatory (alpha) or inhibitory (beta)
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Beta Adrenergic Receptors
Work by using GCPR's and second messenger systems
Uses cAMP
Inhibitory
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Alpha Adrenergic Receptors
Work by using GCPR's and second messenger systems
Uses a Ca2+
Stimulatory
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Cholinergic Stimulation
Nicotinic or Muscarinic ACh receptors
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Nicotinic Cholinergic Stimulation
```
Always stimulatory (ligand-gated ion channels, either K or Na).
Blocked by curare
```
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Muscarinic Cholinergic Stimulation
Stimulatory or inhibitory, coupled to G-proteins and second messenger
Blocked by atropine
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Nocireceptors
- Pain receptors
- Glutamate and Substance P = main neurotransmitters
- Depolarize when tissues are damaged
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Proprioceptors
Found in muscles, tendons, joins --> sense of body position and fine motor control
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Cutaneous receptors
In the skin, touch pressure, cold, heat, and pain
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Special Senses
sight, hearing, taste etc...
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Exteroceptors
external, respond to stimuli outside
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Interoceptors
internal stimuli, inside organs
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Phasic Receptors
Responds with a quick burst of activity, but quickly adapt and decrease response (i.e. smell)
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Tonic Receptors
Receptors that are slow-adapting; maintain high firing rates as long as stimulus is present (i.e. Pain)
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Generator (receptor) potential
Stimuli produce depolarizations called "generator potentials." Going to keep firing until it reaches threshold. When it reaches threshold, it created an action potential
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Chemoreceptors
Receptors that bind to chemicals in the air or in liquid
| - Taste and Smell
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Gustatory receptors
Taste
| 50-100 specialized epithelial cells
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Olfactory receptors
- In the olfactory epithelium of the nasal cavity
- Sustentacular cells oxidize hydrophobic volatile odors, causing us to react
- GPCR's (metabotropic)
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How smell works
Odor binding cleaves G-protein --> activates adenylate cyclase to make cAMP out of ATP
cAMP opens Na and Ca channels (Causing depolarization) --> graded depolarization that leads to an AP
Up to 50 G-proteins/receptors = increased sensitivity through amplification
Each of the 380 receptors has up to 50 G-proteins
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Vestibular Apparatus (inner ear)
- Provides a sense of equilibrium
- Located in the inner ear
- Consists of Otolith organs and Semicircular canals
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Auditory Ossicles (middle ear)
Tympanic membrane (Ear drum) vibrates, causing the *malleus* (hammer) to hit the *incus*, which then causes the *stapes* to vibrate which will then translate sound to the inner ear, the chochlea
Their job is to translate vibration from the exterior environment to the inner nerves
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Sclera
White part of the eye (collagen fibers), supports and protects
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Choroid
Supplies blood to the eye, middle layer
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Retina
Contains photoreceptor neurons, for photoreception, transmits impulses
- Forward extension of the brain, so the neural layers face outward toward the incoming light (bad design)
- Rod and cone shaped photoreceptors
- Pigment epithelium
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Lens
Transparent, refracts light and focuses onto fovea centralis
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Cornea
Transmits and refracts light
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Iris
Pigment cells and smooth muscle fibers, regulates the diameter of the pupil
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Pupil
The black part of the eye, where light enters
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Myopia
Elongated eyeball, nearsighted
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Hyperopia
Shortened eyeball, farsighted
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Astigmatism
Asymmetry of the cornea and/or lens
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Optic Disc
Blind spot, where neuron axons are gathered and exit as the optic nerve
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Photoreceptors
Rods and cones
Outer segment: Full of flattened discs with photopigment molecules
Inner segment: contains organelle's
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Retinal Pigment Epithelium
Single layer of cells located under rods and cones
| Helps vision by: Phagocytizing shed outer discs and Absorbing scattered light
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Rods
Black and white, contains rhodopsin
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Rhodopsin
Absorption of light causes dissociation into retinaldehyde and opsin = bleaching reaction
Your actual photopigment
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Retinaldehyde
Also called retinal, derived from vitamin A
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Visual Cycle of Retinal
Typically 11-cis form in rhodopsin
Bleaching turns to all-trans form
Must be converted back to 11-cis in pigment epithelial cells
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Dark current
In the dark, photoreceptors inhibit (hyperpolarize) bipolar cells
Na channels in rods and cones are always open, so the cells are always depolarized (action potential)
This depolarization causes them to release a neurotransmitter, hyperpolarizing them
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Trichromatic
3 cone types (S: short, blue; M: medium, green; L: long, red)
Instead of opsin, have photopsins
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Fovea Centralis
A little dip, the portion of the retina where vision is the best
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Polar Hormones
Water soluble
Can't pass through membranes, must be injected if used as a drug
Receptors are on the cell membrane
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Non-polar Hormones
Insoluble in water
Lipophilic hormones, they can dissolve really easily in a plasma membrane, they can pass through easily
Receptors are inside the cell
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Endocrine Glands
Ductless: secrete hormones directly into blood
| Hormones carried to target cells with receptors
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Hormones
Regulate body metabolism, growth, and reproduction.
They have high specificity (Lock and key fit), high affinity (bond strength), and low capacity (not many receptors, easily saturated)
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Lipophilic Hormones (nuclear hormone receptors)
i.e. steroid and thyroid
Need *carrier proteins* to help carry them through the blood stream to target cells where they dissociate from carrier and diffuse across plasma membrane
- Activate genetic transcription by hormone binding --> act as transcription factors (help transcription) --> produce new proteins metabolic changes inside cell
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Nuclear Hormone Receptors
Two Domains: ligand-binding and DNA-binding
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Genomic Hormone Receptors
- Stimulates genetic transcription
- Receptors usually in cytoplasm, sometimes in nucleus
- Hormone binds to receptor then translocates to nucleus
- Hormone-receptor complex binds DNA hormone response element
- Hormone response elements have 2 "half-sites"
- 2 ligand-bound receptors must bind = dimerization
- Dimerization forms homodimer of 2 of the same complexes
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Coactivators and Corepressors
Can change effects of a given hormone in different cells
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Thyroid Hormone Action
Hormone response element on DNA has 2 half-sites: 1 for T3 receptors (TXR) and another for a 9-cis-retinoic acid receptor (RXR)
T3 binding removes corepressors
Binding proteins help T3 get into the nucleus
Only when TR and RXR bind to the hormone response element is a gene activated
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Thyroxine
T4, four molecules of iodine, complexed to thyroxine-binding globulin (TBG) and travels to target cells
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TXR Receptor
For triiodothyronine (T3, Activated thyroid hormone)
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RXR Receptor
Other half-site, for 9-cis-retinoic acid
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Polar Hormones That Use 2nd Messenger
```
Bind to receptors on the cell surface
2nd Messenger Systems:
- Adenylate cyclase
- Phospholipase C
- Tyrosine kinase
```
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Adenylate Cyclase (cAMP) System
Used by epinephrine and norepinephrine
- Binds to beta-adrenergic receptors
- G-protein dissociates (alpha-subunit) --> activates adenylate cyclase
- Adenylate Cyclase converts ATP to cAMP
- cAMP activates protein kinase, altering cell metabolism
- cAMP inactivated by phosphodiesterase
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Homodimer
Two of the same complexes (i.e. Steroid)
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Heterodimer
Two different complexes (i.e. TXR and RXR)
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Phosphodiesterase
Deactivates cAMP
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Phospholipase C System
Used by epinephrine in some cells
- Binds to alpha-adrenergic receptors
- G-proteins dissociates, activate phospholipase C
- Phospholipase C produces IP3 and DAG
- IP3 releases stored Ca+ from ER
- Ca+ activates calmodulin which activates protein kinases
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Calmodulin
Activates protein kinases to modify other enzymes, altering cell metabolism (phospholipase C system)
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cAMP
Activates protein kinase, phosphorylating target proteins, altering cell metabolism (Adenylate Cyclase System)
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Tyrosine Kinase System
Used by insulin and growth factors
- Receptor is also a tyrosine kinase enzyme (ligand outside, enzyme inside)
- Ligand binding causes autophosphorylation
- Phosphorylates Insulin receptor substrate proteins, activating other signaling molecule
- Signalling cascade occurs
