Exam I Flashcards
Describe the mechanism of muscle contraction
- nerve impulse triggers release of ACH into synaptic cleft - initiates muscular impulse
- as muscle impulse spreads to T-tubulues, Calcium ions are released
- Calcium ions bind to troponin - troponin changes shape, moving tropomyosin and exposing actin binding sites
- Myosin binds to exposed actin sites
- Myosin heads pivot, moving thin filaments toward the sarcomere center. ATP binds myosin and is broken down into ADP. Myosin detach from thin filaments and return to original position.
- Repeat of step 5 results in sliding of thick and thin filaments past one another (contraction)
- When impulse stops, calcium ions are transported into sarcoplasmic reticulum, tropomyosin reverts back, and filaments relax
Understand compartmentalization of body fluids
Total Body Water: 60%
ICF: 40%
ECF: 20%
ECF split:
- -ISF: 15%
- -Plasma: 5 %
transcellular fluid: CSF, digestive secretions, synovial fluid, etc.
Know types and examples of membrane transport especially passive vs. active transport
- Active transport: against gradient & requires ATP
A. Primary: Na/K+ ATPase
B. Secondary: carrier mediated; uphill (SGLT glucose) - Passive transport: with gradient; no energy
A. Facilitated diffusion: GLUTS
Discuss difference between electrical and chemical gradients
Electrical gradient: electrical force
Concentration gradient: chemical force
- at equilibrium: no net movement of ions
- determined by ion conc. gradients
- ***K+ (leak)
- ***Na/K+ pump (low intracell. Na; High intracell. K+)
What is the normal resting membrane potential across the membrane?
-70 to -80 mV
- established by diffusion potentials
- K+
Know everything about each stage of an action potential
- Upstroke: Depolarization (less neg.)
- -open voltage gated Na channels
- -Na influx - Overshoot
- -influx of sodium
- -potential very + - Falling: Repolarization
- Voltage gated K+ channels open
- Na channels close - Undershoot (Hyperpolarization)
- slow closure of K+ channels
Fiber types
A-fast (somatic sensory)
B-Fast (pre-ganglionic ANS)
C-slow (pain, temp; post-ganglionic)
Describe Skeletal Muscle activation
- action potential
- Depol along T-tubules
- Ca2+ release
- Ca2+ binds troponin C
- expose myosin binding site
- cross-links
Describe SM activation
- stimulus for Ca2+ entry into cell
- Inc. intracellular calcium
- Binding of Ca2+ to calmodulin
- myosin light chain kinase
- phosphorylation of light chain kinase
- Inc. myosine ATPase
- myosin-actin binding
Autonomic regulation is coordinated by
hypothalamus and brain stem
The nervous system is split into somatic and visceral. Describe visceral
Afferent: Viscerosensory
Pain (e.g., ischemia,
distension, cramping)
& REFLEX
Efferent: SM & CM and glands
Describe origins of sympathetic vs. parasympathetic
Sympathetic:
– “Thoracolumbar”
Intermediolateral cell column T1-L2 (IML) of SC
Intermediate gray: sympathetic pre-ganglionic neurons
Parasympathetic
- “Craniosacral”
- CN’s 3,7,9,10 *
- S2-S4
The adrenal medulla is a specialized ganglion in the sympathetic division of the autonomic nervous system. The cell bodies of its pre-ganglionic neurons are located in the thoracic spinal cord. They travel to the greater splanchnic nerve where they synapse and release
Ach on nicotinic receptors
- secretes mainly epinephrine
- -PMNT
Sympathetic have ___ pre- and ___ post ganglionic cells. Parasympathetic have ___ pre and ___ post.
Sympathetic:
- Pre = short; Ach to nicotinic
- Long post = Norepinephrine; adrenergic receptors
Parasympathetic:
- Pre = long (Ach, nicotinic)
- Post = short (Ach, muscarinic)
Sympathetic pre-ganglionic and post-ganglionic info
Pre:
T1-L2 lateral horn
Post:
- paravertebrl ganglia (sympathetic chain)
- pre-vertebral ganglia (celiac)
- adrenal (chromaffin)
Parasympathetic pre-ganglionic vs. post-ganglionic
Pre: CN 3, 5, 7, 9
Post: wall/effector organs; associated with CN
Adrenoreceptors (Sympathetic)
- Inc. heart
- Constricts SM vessels
- Dilates SK (SM) vessels
- Dec. GI motlity
- Bronchodilator
- Ejaculation
- Relax bladder wall; constrict sphincter
- Inc. sweating (M sympathetic)
- Dilates pupil (eye)
- Inc. renin
- Inc. lipolysis
a1:
- vascular SM
- GI, sphincters
- bladder
- iris (radial muscle)
a2:
- GI
- adrenergic neurons
B1:
- heart
- salivary
- adipose
- kidney
B2:
- cronchioles
- skeletal muscle SM (vascular)
- GI
- bladder
G-proteins and their receptors
GI: inhibition of cAMP
–A2, D2, M2
Gs: Inc. cAMP, adenylyl cyclase
–B1, 2, 3 & D1
Gq: Phospholipase C, IP2, DAG; Ca2+
-M1, M3, A1
Spinal cord arrangement
Inner: gray (neuronal cell bodies)
Outer: white matter (tracts; myelin)
Dorsal: sensory
Ventral: Motor
DRG: all sensory info from periphery and CNS (pseudounipolar)
Somatotropic organization: the lateral cortex controls
Face and arms
Somatotropic organization: the central gyrus is split into pre and post. What neurons are in these sections?
Pre: primary motor
post-primary sensory
PCMl detects
discriminative touch, pressure, vibration, two point discrimination, proprioception
ALS detects
pain, temp, light touch
PCML lower extremity signals travel through what fasciculus? Upper?
Lower: Midline: grascilis fasciculus
Upper: cuneatus fasciculus