Block 1 Flashcards
pH (ECF)
7.4
pH (ICF)
7.1
Steady State
requires energy for maintenance, homeostasis
Equilibrium
no energy transfer
Feed-Forward Control
Body anticipates a change (start line of a race, salivation when smelling food)
Set Point Deviations
Circadian rhythm, environmental changes, fever, aging
Hypotonic
Cells expand and may burst with water gain
Hypertonic
Cells shrink due to water loss
Dehydration
Water loss from plasma leads to water loss from interstitial compartment which leads to water loss from cells and hence cellular shrinking
Diffusion
Down concentration gradient
- Direct diffusion: directly through membrane
- Channel-Mediated Transport: pores
- Facilitated Diffusion: conformational change (ion channels and carrier proteins)
Active Transport
Energy source needed to move solute AGAINST its concentration gradient
- Primary: Na/K pump, carrier mediated
- Secondary: glucose, carrier mediated
Endocytosis
Engulf part of the extracellular fluid, pinch off and internalize those vesicles into the cell
Exocytosis
Intracellular membrane-bound vesicle within the cell moves to the plasma membrane, fuses with it, and releases contents into extracellular fluid
Depolarization
cells whose membrane charges following the influx of Na+ into the cell, more positive Vm
What are the 3 components of homeostatic regulation mechanism?
Receptor, regulatory center, effector
Excitability
tissue that is capable of generating and responding to an electrical signal
Adequate stimulus
an act applied to a living thing that is strong enough to evoke a response
Responce
the reaction of an organism once adequate stimulus has been applied
Resting potential
the phase in which there are more K+ gates open than Na+ in the membrane
Hyperpolarization
also called the undershoot, where the membrane potential moves towards the K equilibrium
Repolarization
the process of recovering a normal membrane voltage
Negative Feedback Mechanism
signals sent through a loop system aimed at reversing a change in a controlled environment
Positive Feedback Mechanism
a feed back loop in which the response re enforces the stimulus, triggering an amplified response
Osmolarity
the number of osmotically active particles per VOLUME of water
290
(275-295)
Osmolality
the number of osmotically active particles per WEIGHT of water
Tonicity
PRESSURE caused by the osmotic gradient across cell membrane, only non penetrating molecules
Osmotic pressure
pressure required to prevent water movement across a semi-permeable membrane
Resting State
activation gate closed and inactivation gate open, minimal flux of Na
Membrane Potential
the potential difference between the inside and outside of the cell
Equilibrium Potential
the potential at which there is no flux of a given ion
Summation
mult. signals arriving at the trigger zone are (summed)
Temporal summation
Graded potential (sum together)
- change in frequency of stimulation (time)
- single neuron fires many times
Spatial Summation
Graded potential
-mult. inputs at different locations on neuron (space)
Myasthenia Gravis
Autoimmune disorder -anti bodies block nicotinic receptors -weakness, droopy eye, double vision -Anticholinesterase drugs: neostigmine allows ACh to remain at the NMJ
Inotropism
Ability of myocardial cells to change the strength of contraction
-heart exposed to an inotrope can potentially generate more isotonic force and move a greater load faster and farther
Where is smooth muscle found?
vasculature, respiratory, gut
Frontal lobe
Motor planning and commands, impulse control, working memory, judgement
Parietal lobe
reception and perception of sensory information
Temporal lobe
auditory, memory
Occipital lobe
visual processing
limbic lobe
emotions, memory
Insular lobe
gustatory sense (taste)
Limbic System
Grey matter in brain
- cingulate gyrus: emotion
- Thalamus
- hippocampus: learning and memory
- amygdala: emotion and memory
Association Tracts
conduct nerve imposes between gyri in the same hemisphere
Commissural Tracts
conduct nerve impulses from gyri in one cerebral hemisphere to corresponding gyri in other hemisphere
Projection Tracts
conduct nerve impulses from the cerebrum to lower parts of the CNS or vice versa
Cerebrospinal Fluid produced?
Choroid plexus
ependymal cells, Pia mater, fenestrated capillaries
Flow of CSF
lateral ventricles —>third ventricles–>4th ventricle—>subarachnoid space—> intracranial sinuses –> blood stream
Functions of CSF
Shock absorber, provides nutrients and removes toxic waste, diagnostic tool
Blood Brain Barrier
tight endothelial cell junctions, induced by paracrine signals from astrocytes feet
- functional barrier made up of capillaries between interstitial fluid
- no BBB: hypothalamus, vomiting center
Functions of BBB
maintains a constant environment and protects brain from toxins, prevents the escape of neurotransmitters from the CNS to the general circulation
Diencephalon
- Thalamus: relays and modulates sensory information traveling to the cortex and integrates motor information traveling from basal ganglia and cerebellum to cortex
- Hypothalamus: homeostasis and the endocrine system
- Pituitary Gland: endocrine/neuroendocrine gland
- Pineal Gland: secretes melatonin
Brain Stem
Midbrain, pons, medulla oblongata
-regulates: HR, breathing, consciousness
Cerebellum
Movement, memory of skills and movements, coordination, and speech
Blood supply to the brain
Internal Carotid artery and subclavian artery
Meninges
Dura mater
Arachnoid
Pia Mater
Cervical spinal nerves
8
Thoracic spinal nerves
12
lumbar spinal nerves
5
sacral spinal nerves
5
coccygeal
1
Good supply to the spinal cord
Anterior longitudinal artery and 2 posterior longitudinal arteries (branch of the subclavian)
Sensory neurons
from the receptors to CNS
Motor neurons
from the CNA or ganglia to effector cells
Interneurons
communicating and integrating network
Oligodendrocytes CNS
forms and maintains the myelin sheaths of multiple axons
Astrocytes CNS
strengthens and support neuronal tissue, forms the BBB, homeostatic environment
Microglia CNS
phagocytic
Ependymal cells CNS
produce and secrete CSF
Schwann cells PNS
myelinated 1 portion of an axon
Satellite cells PNS
structural support
Adequate stimulus
respond to a particular form of energy
transduction
covert stimuli into electrical signals
convergence
decreases 2 point discrimination
Pacinian Corpuscle
touch receptors of the skin
- lies deep in the dermis
- responds to VIBRATION
- large receptive field
- rapidly adapting
Ruffini’s endings
touch receptors of the skin
- Slightly smaller than PC
- deep in dermis
- responds to skin stretch
- large receptive fields
- slow adapting
Meissner’s Corpuscle
touch receptors of the skin
- located on the ridges of glabrous skin (ridges of fingerprints)
- responds to flutter, stroking
- small receptive field
- rapidly adapting
Merkel’s Disc
touch receptors of the skin
-located on superficial layers of the skin
responds to steady pressure and texture
-small receptive field
-slow adapting
Free Nerve Endings
- located around hair roots and under skin surface
- responds to various stimuli
- variable adaptation
Somatic Nervous System
Voluntary control (joints, skin, striated muscle)
Autonomic Nervous System
Involuntary to/from smooth muscle, cardiac muscle and glands
Sensory
brings info from world to CNS
Motor
sends info from the CNS to the world
Dorsal Columns Medial Lemniscus Tract
Cross over at the Medulla
-Touch Receptors
Thalamus–> Parietal lobe –> post-central gyrus –> Brodmann areas 1, 2, 3a, 3b (primary somatosensory cortex)
Cortical Map Plasticity
Dynamic and adjust depending on the amount of sensory experience
Nociceptors
Located in the meninges not brain!
-activated by stimuli that have the potential to cause tissue damage
AB
Sensory nerve fiber
Mechanoreceptors of skin (very myelinated)
AS
Sensory nerve fiber
Sense cold, fast pain, myelinated
C
Sensory nerve fiber
Slow pain, heat and cold, itch, unmyelinated
How do pain signals get to the brain?
Antero-lateral system or spinothalamic tract
-cross over spinal cord? (immediate)
The Gate-Control Theory of Pain
Tonically active inhibitory interneurons suppress pain pathway
-with strong pain the C fiber stops inhibitions of the pathway allowing a strong signal to be sent
Prostaglandins
inflammatory mediators- use the COX pathway and inhibit COX pathway of pain
-NSAIDS
Opioid
Endorphins, enkephalins
-heroine, morphine
Taste Cells
-taste pore
-trigger AP
Tongue–> brainstem–>thalamus–> gustatory cortex
Olfactory
No thalamus
Sound Transduction
Displacement of the cilia in one direction increases the tension on the tip link and increased the influx of potassium, K+ causes depolarization and entry of calcium which causes the neurotransmitter to be released
Hyperopia
Farsightedness (up close is blurry)
-Treat w/ convex lens
Myopia
Nearsightedness (far away blurry)
-Treat w/ concave lens
Cones
Function under photooptic conditions
-Color
Rods
Function under scotopic conditions
-night, black and white
Accommodation
Eye
Changing the shape of the lens
-Ciliary Muscles: Contracted=lens becomes more round, Relaxed=flatten the lens
Presbyopia
loss of eyes ability to focus
Fovea
Does not have the laminar layer (it is a pit and neurons are pushed off to the side) and light goes in, most acute vision
Optic Disc
Where the optic nerve and blood vessels leave the eye has no photoreceptors “blind spot”
Retina
Has laminar organization
The order in which sound travels through the auditory system?
external auditory meatus, tympanic membrane, ossicles, oval window, scala vestibuli, scala tympani, round window
Lesions of the speech center in frontal lobe results in
failure of coordination of speech muscles
Troponin T (tropomyosin)
attaches troponin complex to tropomyosin
Troponin I
Inhibition, positions tropomyosin over myosin binding site on actin
Troponin C
Ca+2 binds and tropomyosin is moved to initiate contraction
A band
remains constant, all myosin and some actin
H and I band
decrease with contraction
Z band
drawn closer to the ends of the A band with contraction
Calmodulin
Instead of troponin C (smooth muscle only)
Brown Sequard Syndrome
Ipsilateral motor deficit
Contralateral loss of pain and temp
Rapid depolarization
upstroke
Anterior Corticospinal tract
skeletal muscles of the trunk and parts of the limbs
smooth muscle differs from skeletal muscle
different source of calcium
approximate extracellular fluid volumeof a normal individual
20% of body mass
G-protein coupled tastants
bitter, sweet, umami
Block ion channel tastants
sour
Pass through ion channels tastants
salt and sour
IPSP
Gaba and Cl
EPSP
Glutamate and Na
A particular taste can be identified by the pattern of activation of multiple different neurons. Which term best describes this phenomenon?
Population coding
Why is the resting membrane potential -70?
Conductance of K+ is much greater than that of Na+
Upper motor neuron injury
positive babinski
Golgi Tendon
discriminates weight when we are lifting
