A Phys - Quiz 6 info (p. 88-124) Flashcards
What are the differences between invertebrate and vertebrate light reception
- invertebrates have PLC made as teh 2nds messenger from the G-protein (transducin) and that is used to stimulate PIP2 in the membrane which in turn makes IP3 and DAG. These two messengers close the Na+ channel and stop Na+ influx.
PIP2 stands for;
Phosphatidyl 4, 5-bisphosphate
DAG stands for;
Diacylglycerol
IP3 stands for;
Inositol triphosphate
PLC stands for;
Phospholipase C
PDE stands for;
phosphodiesterase
When the invertebrate photoreceptor cell is exposed to light, what happens?
- the cell depolarizes, moving away from the K+ Nernst pot.
- there is increase G(Na) (maximum sodium conductance)
- it is moving towards 0/towards E(Na)
- when light is no longer on, the cell hyperpolarizes (Na+/K+ ATPase) and returns to a negative, resting potential.
When the vertebrate photoreceptor cell is exposed to light, what happens?
- the cell is close to zero and hyperpolarizes towards the K nernst potential
- there is a decrease in G(Na) (maximum sodium conductance
- once the light is off, the potential depolarizes as Na+ influxes.
What is the ERG? What is it used for?
It is an electroretinogram that tracks the electrical activity of the retina in response to light stimulus
What is the a wave in an electroretinogram?
it is hyperpolarization due to inhibition of dark current in photoreceptor cells, it is the first movement and it is downward on a graph; it happens immediately after light is applied.
What is the b wave in an electroretinogram?
it is the depolarization of bipolar cells, it is second wave and is significantly larger than the a wave; it happens directly after the a wave and happens while light is applied.
What is the c wave in an electroretinogram?
it is the interaction between photoreceptor cells and pigmented epithelium; this happens after the light is turned off and it is a signal that these cells are functional (bc they are wrapped around photoreceptor cells)
Across a turtle, toad, rabbit and human, how are the ERGs similar and different?
Similar:
- they all have an a and b wave
- the a and b wave are in the same directions as human waves
Different:
- the toad and turtle have a d wave as well
- there is variability in the amount of volts and milliseconds for each
What is nociception?
the detection of painful/noxious stimuli
Mechanical nociceptors are most _____, and respond to __________ damage such as: _______, crushing, and _______. These are also the _____ to respond
basic; mechanical; cutting; pinching; fastest
Thermal nociceptors respond to _________ extremes, they are enabled by _______ _____ channels that open at certain _______
temperature; TRP cation; temperatures
Polymodal nociceptors are most _____ and respond ______ to all kinds of damaging stimuli; they respond to _____ released from ______ tissues. It takes _____ to work but senses pain over a ______ ______.
complex; equally; chemicals; injured; longer; long period
_____ _____ activates nociceptors
tissue damage
What do damaged cells release?
signaling chemicals, 5-HT, bradykinin, prostaglandins
What do chemicals like 5-HT, bradykinin and prostaglandins open?
cation channels on nociceptor cells and trigger APs down the dorsal root ganglion neuron
How do nociceptors send signals to the brain?
they synapse in the spinal cord with afferent neurons to the brain
What are some characteristics of pain?
- initial sharp twinge of pain via the fast pain pathway
- secondary, diffuse wave of pain shortly after + occurs via the slow pain pathway
What is involved in the fast pain pathway (+ characterize it)
characterization: initial sharpe twinge of pain
Involved:
- mechanical nociceptors
- thermal nociceptors
What is involved in the slow pain pathway (+ characterize it)
characterization: secondary, diffuse wave of pain shortly after painful stimuli
involved:
- triggered by chemicals released by damaged tissue + detected by polymodal nociceptors
- prolonged pain
What is true about the nervous system across organisms?
different organisms have different structures and complexities of a nervous system, the human has a very complex nervous system while the sea star contains a neural ring and some radial nerves.
What are neural nets?
a connected series of neurons who do a specific function
What are ganglia?
a collection of nerves with an entrance and exit point for integration
What happens to the amount of branches closer to the brain?
There are more branches closer to the brain and less branches further from the brain.
What are some functions of the CNS that all mammals and vertebrates can do
1) Subconsciously regulate
2) Voluntarily control movement
3) Conscious awareness of body and surroundings
What are some other functions of the CNS that only mammals can do
4) Experience emotions
5) Engage in higher cognitive processes (thought/memory)
Monosynaptic reflex arc/loop information flow in the NS
the stimulus on tissue and travels along the axon (via neuron with cell body on outside of cell) until it reaches a synapse (central nervous system) and the NTs evoke some type of response in the postsynaptic cell. There can be a motor neuron that then releases NTs into an effector cell
common in humans
Single-cell connection of information flow in the nervous system
the stimulus hits the tissue, and dendrites are embedded into the tissue. The dendrites are connected to the soma/receptor cell and the AP is fired, it travels along the axon until the axon terminals which are attached to the effector cell
Polysynaptic reflex arc information flow in the NS
The stimulus causes dendrites in receptor cell to influence an afferent sensory neuron through APs and NTs. This then synapses on an interneuron and that synapses to an efferent motor neuron (these two neurons are part of the central nervous system), the efferent motor neuron produces some change in the effector cell.
What are the three main functional classes of neurons?
Afferent, efferent and interneurons
Afferent neurons can _____ the _______ environment and send signals to __ __ __
+ some examples are:
sense; peripheral; CNS
- inner hair cells, gustatory cells, nociceptors
Efferent neurons can _____ CNS information/commands to _____ organs
+ one example is:
transmit; effector
- motor neurons
Interneurons can _______ ______ information, coordinate ______ response, and modify both types of information content. This is only in __ __ __ and most abundant neuron type: ______ _____ neurons
integrate afferent; efferent; CNS; higher-order neurons
Interneurons are cool because:
- they have more complex/finer control and the integrator is modifying affarent information -> shows complexity of NS
A unipolar (sensory) neuron is characterized by:
- the dendrites are getting information from one area/they are embedded into one area and the dendrites are not on the cell body (cell body off to side of axon)
A multipolar (inter- and motor) neuron is characterized by:
dendrites are getting information from many different sources because they are pointing in many different directions. The dendrites are connected to the cell body and from the cell body, an AP travels down axon
What can we see between the NS’s of an amphibian and mammal?
- the functional NS is preserved
What is the lateral line?
a system of sensory organs used to sense movement, vibration and pressure in the water surrounding the aquatic animal. (fish, sharks, mantas, etc.)
What is a dermatome?
one set of spinal nerves that control one block of muscle
The evolution of the lateral line system shows that…
…as fish get more complex, the lateral line system gets more complex
The dermatome is helpful to know for ______ anatomy and NS too. We know that the function of dermatomes here is for the ______ of ____________ surfaces of the _____.
human; mapping; somatosensory; body
What are the supportive CNS cells?
Glial cells
What are the four types of glial cells?
- oligodendrocytes
- microglia
- ependymal cells
- astrocytes
Oligodendrocytes _____ ____ sheaths for _ _ _ neurons
form myelin; CNS
Microglia ________ microorganisms, cellular _____ from dying or _____ cells, and regulate _____ networks
phagocytize; debris; injured; neuronal
Ependymal cells _____ and monitor __________ fluid that circulates ____ and ______ throughout the CNS via the __________ system
synthesize; cerebrospinal; nutrients; ions; ventricular
Astrocytes ____and establish the ___ - ____ barrier, supply _____ with compounds for making _____, and transfer ______ to neurons
regulate; blood-brain; neurons; NTs; mitochondria
What direction is the ventricular system of the cerebrospinal fluid through CNS
- it is 2-directional and keeps fresh fluid
The blood to brain must pass a _____ _____: brain ________ are sealed via _____ ______
selective barrier; capillaries; tight junctions
What are some of the things that must be transported into brain from blood by membrane transport proteins?
- glucose
- amino acids
- ions
so this is highly selective
What are some exceptions in the blood-brain barrier?
- O2, CO2, alcohols and steroid hormones
- these diffuse through the membrane bc small or lipophilic
Astrocytes ____ partially (only where pores) around ______ to physically regulate CNS –> _____ transport (and vice versa)
wrap; capillaries; blood
Astrocytes also maintain _____ concentrations in ____ environment.
ionic; interstitial
Through maintaining ionic concentrations: __ _ channels (ex: Kir 4.1) in astrocytes allow __ _ in one area and then out into the _____
Gene mutations for Kir 4.1 associated with _______
K+; K+; blood
epilepsy
Through maintaining ionic concentrations: astrocytes _______ extracellular __ _ when __ _/__ _ ATP____ overwhelmed
remove; K+; Na+/K+; ATPase
What are essential anatomical parts of the brain in vertebrates?
- cerebellum
- occipital/optic lobe
- cerebrum
- pituitary
What are the lobes of the cerebral cortex?
- occipital lobe
- temporal lobe
- parietal lobe
- frontal lobe
What are the functions of the frontal lobe?
- speech formation
- voluntary motor activity
- decision making
- elaboration of thought
What are the functions of the parietal lobe?
- receive and process somatosensory input (touch, pain, temperature)
- memory formation of somatosensory experiences
What are the functions of the temporal lobe?
- processes auditory information (tonal stuff)
- speech understanding (can tell if injury hear if speech of someone else is suddenly garbled to you)
- storing/accessing memory
What are the functions of the occipital lobe?
- initial processing of visual input
- depth-distance perception
- object and individual recognition
What is important about how different things like hearing, seeing, thinking and speaking are shown in brain activity?
- hearing, seeing and speaking are most active in their parts but also show activity across other lobes
- thinking shows activity across all lobes of the brain.
Is motor control efferent or afferent?
It is efferent
Where is the primary motor cortex (precentral gyrus) found?
What does it do?
It is found in the front of the brain, in the frontal lobe
Voluntary movement
Is somatosensory sensation efferent or afferent?
afferent
Where is the somatosensory cortex (postcentral gyrus) found?
What does it do?
It is found in the back of the brain, in the parietal lobe
it senses touch, pain, temp
What divides the primary motor cortex and somatosensory cortex?
the central sulcus (there is some connection between the two sides, not completely separate)
What does the somatosensory cortex do in more depth?
- processes skin-based (somesthetic) sensory info
- nociceptors, thermoreceptors, mechanoreceptors
What does the primary motor cortex do in more depth?
- voluntary control of skeletal muscle
- speech production
- elaboration of thought (decision making, creativity, personality)
Both somatosensory and motor cortices are ________ in innervation, which means the ____ side of the body sends information to the _____ somatosensory cortex.
contralateral; left; right
What can we tell from comparative cortices of mammals?
some mammals have larger proportioning for some parts of the brain area, like a tarsier has a huge occipital cortex (has large eyes) whereas the rat has a huge olfactory nerve (can smell very well). In comparison, humans cannot see or smell as well.
What is a homunculus
The cerebellum is the _______ control of ______ _______
subconscious; motor activity
In the cerebellum there is _____ reception of ________ feedback from somatic receptors in _______ and ______ apparatus (inner ear). There is also ______ reception of ______ input from _______ in primary ________ cortex. There is one other _______ command of _____ position (posture, _______)
affarent; sensory; periphery; vestibular; efferent; motor; neurons; motor; efferent; body; balance
Pathway for control of voluntary movements (6 steps!)
1) what type of input?
2) what happens first when you need to understand stimuli?
3) how/where does the response start?
4) What needs to happen, then?
5) Does anything additional need to happen to make sure it runs smoothly?
6)How do things continue to work/act?
1) Sensory input
2) Integration: planning & decision making center
3) Coordination: cerebellar input
4) Execution: spinal cord to skeletal muscle
5) Maintenance: posture, balance, gait
6) Continuous feedback
What are the two modes of swimming for an organism like the pink helmet jelly?
- slow rhythmic beating of bell
- rapid beats in response to mechanical stimulation
Where is the hypothalamus located?
At the top of the brainstem => evolutionarily older
What is one major hypothalamus function?
physiological setpoint storage, brain area most involved in directly regulating internal homeostasis
What are some other functions of the hypothalamus? (hint: think of regulation and coordination of body functions)
- controls body temp, urine output/thirst, food intake
- regulates hormone production
- coordinates ANS
- regulates emotional and behavioral (especially sexual) patterns
- participates in sleep-wake cycle
The brains stem ______ many _____ ________ functions necessary to support life such as:
- cardiovascular center
- respiratory center
- swallowing center
- emesis center
- sleep center (with hypothalamus)
The ____ _____ originate in _______ and ____/_____ signals to/from ______ organs and ______ organs
cranial nerves; brainstem; send/receive; vital; sensory
Some signals that the cranial nerve sends/receives are…
- senses (vision, audition, gustation, olfaction)
- movements of face, head, neck, throat, eyes (swallowing, chewing, salivation)
- digestive organs and heart monitoring/control
What does the spinal cord do?
- very little processing; primarily afferent/efferent movement of info
What is white matter? What is embedded in it?
It is the myelinated axon tracts and it contains the afferent and efferent tracts
What is grey matter? What is embedded in it?
It is the neuron cell bodies, interneurons
embedded:
- dorsal horn: cell bodies of interneurons
- ventral horn: cell bodies of efferent motor neurons
What are reflexes?
muscle movements occurring autonomously in response to a stimulus
What are the two types of reflexes?
- simple (basic) reflexes
- acquired (conditioned) reflexes
Simple reflexes are _____ and _________
innate; unlearned
Acquired reflexes are a _____ of _____ and ______
result; practice; learning
What is the mechanism of a reflex arc?
1) sensory receptor - responds to stimulus
2) afferent pathway - relay
3) integrating center (spinal cord (simple), brain (acquired)) - processes available information
4) Efferent pathway - relay
5) Effector - carries out response
What are the two neuron chains in the autonomic nervous system?
- preganglionic fiber
- postganglionic fiber
The ________ fiber goes from ____ to postganglionic fiber
CNS; postganglionic fiber
The ________ fiber goes from the preganglionic fiber to _____ ______
postganglionic; effector organ
What does the preganglionic fiber release as NTs?
always releases acetylcholine (ACh)
What does the postganglionic fiber use as NTs to control the effector organ?
- Acetylcholine (ACh)
or - epinephrine/norepinephrine (Epi, NE)
Where do the NTs of the postganglionic fiber go? What is an example of this?
onto receptors in effector organs and tissues. An example is at the neuromuscular junction where a PostG fiber meets the muscle it controls
Sympathetic nervous system has Preganglionic nerves that have what type of fibers and release what NTs? And postganglionic nerves that have what type of fibers and release what type of NTs?
Preganglionic nerves: cholinergic fibers: release ACh
Postganglionic nerves: adrenergic fibers: release NE,
AND
cells of adrenal medulla: release Epi and NE
Parasympathetic nervous system has preganglionic nerves that have what fibers and release what NTs? And postganglionic nerves that have what fibers and release what NTs?
Preganglionic AND postganglionic nerves: cholinergic fibers: release ACh
Parasympathetic nervous system has what type of receptors in the synapse and what type in the effector in the cranio part?
Nicotinic receptor in the synapse and Muscarinic receptor in the effector
(ex of effector organ: cardiac muscle)
Parasympathetic nervous system has what type of receptors in the synapse and what type in the effector in the sacral part?
Nicotinic receptor in the synapse and Muscarinic receptor in the effector
(ex of autonomic effector: adipose tissue [fat])
sympathetic nervous system has what type of receptors in the synapse and what type in the effector in the thoracolumbar part?
Nicotinic receptor to alpha receptor (binds NE and E)
[ex of autonomic effector: smooth muscle]
nicotinic receptor to Beta 1 receptor (binds E and NE)
[ex of autonomic effector for B1 and B2: most exocrine glands and some endocrine glands]
nicotinic receptor to Beta 2 receptor
(binds E only)
SNS and PNS _____ almost ____ of the ____ organs
innervate; all; same
What are the organs that the SNS and PNS innervate?
- eye
- lacrimal and salivary glands
- lungs
- heart
- liver
- stomach
- pancreas
- large intenstine
- small intestine
- rectum
- bladder
- genitalia
ONLY the PNS innervates the:
spleen
