Muscle, Neurotransmitters and Physiology Poutpourri Flashcards
Anchored to M line
Myosin
Extends from one Z line to another Z line
Sarcomere
Component of I band
Actin
Component of H band
Myosin
A band contains
Both actin and myosin
A band does not
change in length
During contraction, I band
disappears and moves toward M line
Where actin is anchored
Z line
Bisects I band
Z line
Bisects the H band
M line
Made up of single myosin tail and 2 myosin heads
Thick bands
Made up of actin with tropomyosin and troponin complex (I, C and T)
Thin filament
Troponin T or
tropomyosin
Attaches troponin complex to tropomyosin
Troponin T
Troponin I function
Inhibits action of actin and myosin
Troponin C function
When bound to Ca promotes interaction of binding of Ca to actin
Contraction steps
Ach binding to motor endplate Opening of Na ch Sarcolemmal depolarization AP spreads until it reaches T tubule Excitation of terminal cisternae of sarcoplasmic reticulum Opening of Ca gates Ca release from SR Ca binds with Troponin C leading to conformational change of tropomyosin Uncovering and exposure of myosin binding site Myosin binds with myosin binding site Cross bridge formation Contraction
Cross bridge cycle
Ca binds to Troponin C
Conformational change on tropomyosin
Exposure of myosin binding site
Myosin head bound to binding site
In absence of ATP remains bound
ATP attachment to myosin head promotes detachment
Hydrolysis of ATP to ADP and inorganic phosphate
Myosin attaches to new site of actin constituting powert stroke (+ end)
ADP released
Rigor state
Relaxation occurs when
Ca is detached from Troponin C
Return of intracellular calcium occurs via entry back to
SERCA
Cardiac Muscle
AP in sarcolemma of muscle fiber
AP spreads into T tubule
Opening of voltage gated Ca ch opens
Extra cellular Ca gets inside cell (lacking in skeletal)
Extracellular Ca binds to Ryanodine receptor
Ryanodine receptor stimulates release of Ca from sarcoplasmic reticulum
(Calcium induced, Calcium release)
Binding to Troponin C
Exposure of myosin binding site
Cross bridge cycling
Relaxation via return of Ca through SERCA to sarcoplasmic reticulum
Smooth Muscle Excitation contraction coupling
Voltage gated Ca ch opens
Extracellular Ca inside cell causes depolarization
Opening of Ca ch in SR
Release of intracellular Ca (Ca mediated, Ca release)
Binding of Ca to calmodulun
Ca-calmodulin activates myosin light chain kinase
MLCK phosphorylates light chains in myosin heads and increases myosin ATPase activity
Active myosin crossbridges slide along actin abd create tension
Source of Ca: SR Site of Ca regulation: Troponin on actin-containing thin filament Pacemaker: No Effects of NS: Excitation Speed of contraction: Slow to fast Rhythmic contraction: No Response to stretch: Contractile strength increases with degree of stretch to a point Respiration: Aerobic and anaerobic
Skeletal
Source: SR and ECF
Troponin on actin-containing thin filaments
Presence of pacemaker
Cardiac muscle
Two typew of muscle spindle
Nuclear bag
Nuclear chain
Muscle spindles are innervated by different kinds of nerve endings:
Annulospiral (primary sensory)
Flower-spray (secondary sensory)
From the primary endings, subserve the monosynaptic stretch reflex
Group IA Afferent
From the secondary endings, terminate on the interneurons on the spinal cords
Group IIA Afferent
Red muscle Ex Soleus Primarily aerobic Small diameter Slow velocity of shortening Oxidative system
Function: Endurance
Slow twitch Type I
Oxidative red muscle
White muscle Ex: Stapedius Metabolism: Primarily anaerobic Large diameter Fast velocity of shortening Phosphagen/Glycolytic System
Function: Delivers power surge for few seconds to minutes
Fast Twitch Type II
Glycolytic White Muscle
More mitochondria
Higher myoglobin, capilary supply
More sensitive to hypoxia
Higher resistance to fatigue
Slow twitch Type I
Fewer mitochondria
Lower capillary supply
Lower myoglobin
Lower sensitivity to hypoxia
Lower resistance to fatigue
Fast-twitch
Only type of muscle without gap junction
Skeletal
Norma nerve resting membrane potential
-70 mv
NT found in pre ganglionic and neuromuscular junction
Ach
Where Ach is produced
Nucleus Basalis of Meynert (Basal Ganglia)
NT produced by locus ceruleus
NE
NE is produced in the adrenal medulla by
Chromaffin cells
Phenylalanine and Tyrosine yield NTs:
Epi
NE
Dopa
Toxin that blocks Na channels of NEURONS
Tetradotoxin of puffer fish and
Saxitoxin
Toxin that blocks Acetylcholine
Botulinum toxin
Botulinum toxin A - derma and aesthetic purpose, neurologic spasticity, spasm and dystonia
Toxin that blocks both GABA and Glycine
Tetanospasmin from tetanus C tetani
Algae causing red tide and algal blooms
Pfeisteria
Amnesia in hippocampus
Anterograde amnesia
Dec ability to retain new information
Type of amnesia caused by thalamic lesion
Retrograde amnesia
Unable to recall events that occured before the development of the amnesia
Bilateral Temporal Lesion
Temporal lobectomy
Loss of social inhibition
Hypersexuality
Kluver Bucy Syndrome
Vestibular system responsible for linear acceleration
Utricle
Saccule
Responsible for angular acceleration
Semi circular Canal
Important neurons in arousal and wakefulness
Orexin neurons
Orexin or hypocretin is produced by the neurons of the
hypothalamus
Loss or destruction of orexin producing neurons cause
Narcolepsy
Nuclei of the brain responsible for ADH/AVP/Vasopressin
Posterior pituitary
Supraoptic nuclei
Nuclei responsible for secretion of oxytocin
Paraventricular nuclei
Posterior pituitary gland
Oxytocin functions
Uterine contractions
Milk let down reflex
Ghrelin is a hormone
for hunger
Leptin is the hormone for
Satiety
Complex phospholipid secreted by type II epithelial cells
Decreases alveolar surface tension to decrease the work of breathing
Surfactant
The type of alveolar cel producing surfactant
Type II pneumocyte
What week does surfactant mature
35 weeks
What do we give to those less than 35 weeks AOG?
Betametasone
Dexamethasone
What are the diseases associated with deficiency of surfactant?
Hyaline Membrane Disease/Respiratory Distress Syndrome of Newborn (Type II)
ARDS in adult is caused by Type I
Bronchopulmonary Dysplasia
Phosphatidylglycerol is also
cardiolipin
Used as marker in VDRL
Cardiolipin
Phosphatidylglycerol
Surfactant
Dipalmitoylphosphatidylcholine
Normal FEV1/FVC ratio
80%
0.80
Phenomenon associated with unloading of oxygen secondary to increased hydrogen
Bohr Effect
Phenomenon associated with unloading of carbon dioxide secondary to increased oxygen?
Haldane effect
Increased oxygen delivery to the tissues when carbon dioxide and hydrogen ions shift the oxygen-hemoglobin dissociation curve
Bohr effect
Release of carbon dioxide when oxygen binds with hemoglobin
Haldane effect
Where is EPO produced?
Peritubular capillaries of the kidney
Enzyme is present in the kidney to convert Vitamin D in its active form
1 alpha hydroxylase
Active form of Vitamin D
1,25 Dihydrocholecalciferol
Vitamin D deficiency in children is known as
in adults
Rickets
Osteomalacia
What is the functional unit of the kidney?
Nephron
Secrete renin
JG cells
The components of juxtaglomerular apparatus:
JG Cells
Macula densa
Mesangiel cells
Senses changes in volume and decrease in NaCl concentration
Macula densa
Normal protein content of the urine?
0
First urge to void is felt at a bladder volume of about
150 ml
Marked fullness of the bladder at about
400 ml
What substance would be secreted in response to changes in BP by JG cells of the afferent arterioles?
Renin
Renin action:
Converts Angiotensinogen from the liver to Angiotensin I
ACE converts
Angiotensin I to Angiotensin II
No active sodium transport
Highly permeable to water
Descending limb
Actively pumps sodium out of tubule to surrounding intersititial fluid
Impearmeable to water
Ascending limb
Impermeable to urea
TAL
DCT
Cortical CD
Where is aldosterone specifically produced?
Zona glomerulosa of cortex
What is the Specific action of ADH on the kidney
Causes insertion of aquaporins/water channels on the distal tubules
ADH receptors in distal tubules are affected
Lithium
Nephrogenic DI
Renal threshold for glucose
180 mg/dl
What is the strongest stimulus for erythropoeitin secretion?
Hypoxia
Smallest branchest of the arteries
The site of highest resistance in the cardiovascular system
arterioles
Contain the highest proportion of blood in CV system
Veins
The muscle length prior to contractility and it is dependent of ventricular filling or EDV
Preload
The value is related to right atrial pressure
Preload
Most important determining factor of preload
Venous return
The tension or the arterial pressure against which the ventricle must contract
If arterial pressure increases, afterload also increases
Afterload
Preload =
EDV
Afterload =
End systolic wall stress/tension or Resistance
Is the volume of blood pumped each minute and is expressed by the equation:
Cardiac Output = SV x HR
RMP of GI Smooth Muscle
-40 to -80 mV
Slow waves produced by the
Interstitial Cells of Cajal
Predominant excitatory neurotransmitter of GI
Acetylcholine
Para
Inhibitory neurotransmitter of GI tract
VIP
NO
Stomach secretes approximately this amount of gastric juice everyday
2 L
Most important of the pancreatic enzymes for digesting proteins
Trypsin
Chymotrypsin
Carboxypolypeptidase
CCK is secreted by
I cells
What is the effect of CKK on the Sphincter of Oddi?
GB contraction
Sphincter of Oddi Relaxation
Maximum amount the GB can hold
30-60 mL
Bile salts in the intestinal tract:
Emulsifying or detergent function of bile salts
