Physiology lecture 6.txt

What are the differences between smooth muscle and skeletal muscles (7); lack striations, less myosin, no troponin (calmodulin), dense bodies not z lines, involuntary (responds to more than just excitatory stimulus but also stretch, chemicals, temperature), Ca from ECF (less developed SR), slow sust...

What are the differences between smooth muscle and skeletal muscles (7); lack striations, less myosin, no troponin (calmodulin), dense bodies not z lines, involuntary (responds to more than just excitatory stimulus but also stretch, chemicals, temperature), Ca from ECF (less developed SR), slow sustained contractions What is the role of dense bodies; actin is bound here and anchored to the ECF and other smooth muscles to create work Compare contractions of skeletal muscles to smooth; smooth muscles are slower sustained; create more tension over a long period of time Where is smooth muscles located in vessels; tunica media How are neurons connected to a smooth muscle; they are not connected directly, no neuromuscular junction like seen in the skeletal muscleWhat type of neurons connect to a smooth muscle; autonomic nerves NOT somatic What is particular to autonomic neurons at the junction of smooth muscles? Contain variscositiesWhat is a varsicosity; a swelling of the neuron where NT is storedWhat NT do autonomic nerves release; norepinephrine and acetylcholineNorepinephrine is associated with what system; sympathetic Acetylcholine is associated with what system; parasympathic Smooth muscle can undergo ________ and __________ (uterus); mitotisis, hyperplasiaWhat is the arrangement of smooth muscle in the viscera; circular and longitudinal What is the purpose of smooth muscle in the viscera being circular and longitudinal; longitudinal allows muscle is scrunch like a slinky and circular allows controlling of lumen size What are the two major types of smooth muscles; multi unit or single unitDescribe multi unit smooth muscles (3); can have own autonomic nerve connection, do not fire spontaneously, do not contract in response to stretch What is significant about having its own autonomic nerve connection; allows for more fine tuning like the iris, comparable to the amount of motor units recruited in skeletal muscleWhat is more abundant single unit or multi unit; single unitDescribe single unit (4); contain gap junctions, contract as a unit (AP propagate from cell to cell), can be spontaneously active (fluctuating threshold potential), stretch can induce contractionWhy are single units structured that way; to allow for uniform movement like in the GI so muscles can depolarize all at once What are the ways we can stimulate SM; autonomic nerves – NT (excite or inhibit), chemicals – hormones, CO2, O2, NO, low pH, temperature, stretch What ways can Ca concentration increase in the cell; “leak channel”, voltage gated channel, ligan gated channel, stretch activated channel, via a second messenger IP3 pathway, calcium induced calcium released What ways does Ca concentration decrease (reset); Ca ATPase out of the cell, Ca ATPase into the SR, Ca2+/Na+ countertranspoterDescribe the SM contraction pathway; 1. Ca+ enters via Ca+ channels, 2. Ca binds to calmodulin to form Ca-Calmoudilin 3. Ca Calmodulin activates myosin light chain kinase (Ca Calmodulin MLCK) complex which phosphorylates light chain on the myosin head (1) and this activates myosin ATPase which cleaves ATP into ADP and Pi and sets it in the cocked position (increases affinity of the myosin head) (2), 4. myosin heads binds to actin and pull actin back toward its tail, actin pulls on dense bodies and the cell contracts and ADP and Pi is cleaved. 5. ATP comes back and removes the myosin head from actin and resets the cross bridge cycle. 6. If more Ca is available, then cycle begins again What is phasic concraction; contraction pathway that is similar to skeletal muscle but occurs in smooth muscle What removes Pi from myosin – phosphataseWhat causes muscle relaxation in smooth muscle contraction cycle; Removal of Ca and removal of Pi on myosin via phosphataseDescribe tonic contraction (latch bridge mechanism); once myosin binds to actin and waiting for ATP to come in and remove myosin head actin, a phosphatase comes in and cleaves Pi, this leaves the myosin head binded to actin but without the Pi, ATP has lessened affinity to bind and remove that myosin headWhat is significant about the latch bridge cycle; helps to maintain a long period of tension to help reduce energy consumptionWhat division is smooth muscle innervated by; the visercal efferent motor Where do the neurons originate for the parasympathetic; cranial nerves 3,7,9 and 10 and sacral portion of the spinal cordWhere does the neurons originate for the sympathetic; T1-T12 and upper 2-3 upper segments of the spinal cord Describe the enteric NS – semiautonomous and can operate reflexively without input from CNS, modulated by the ANS Preganglionic fibers are un/myelinated; myelinatedPostganglionic fibers are un/myelinated; unmyelinated What is meant by ANS neurons have tonic acitviyt; it means that sympathetic and parasympathetic never fully turn off and on, they are always working in tandem and can increase or decrease acitivity but never ‘shut off’What NT is released from the presynaptic neuron in a typical neuron; ACHWhat receptor does the NT bind to on the postsynaptic neuron in a typical neuron; nACHRWhat NT is released at the postsynaptic neuron; NEWhat NT is released at the presynaptic neuron in adrenal innervation; ACHWhat receptor does NT bind to on the adrenal glands, what cell?; nACHr, chromatin cellsWhat NT is released from the adrenal glands in adrenal innervation; EP and NE Where do the adrenal glands release NT to; directly into the blood stream Presynaptic neurons usually (shorter/longer) than postsynaptic neurons in sympathetic innveration; shorterWhere does sympathetic innervation release ACH instead of EP and NE; sweat gland innervation Presynpatic neurons in parasympathetic innervation are (shorter/longer) than postsynaptic neurons; longer What presynaptic neuron in parasympathetic innveration releases what NT; ACHWhat receptor is found on postsynaptic neurons in parasympathetic innervation; nACHWhat NT is released from the postsynaptic neuron in the parasympathetic innervation; ACHWhat receptors on target organs are found in parasympathetic innervation; musculatinic mACHrWhat CN are involed in pararsympathetic innervation; CN 3, CN 7, CN 9, CN 10 What seven effects of parasympathetic innervation were discussed in lecture; 1. Constricts pupils, 2. Stimulates saliva production, 3. Constricts bronchi, 4. Slows heart, 5. Stimulates stomach, pancrease, and intestines, 6. Stimulates urination, 7. Promotes erection of genitals What nine effects of sympathetic innervation were discussed in lecture; 1. Dilates pupils 2. Inhibits saliva production, 3. Dilates bronchi, 4. Accelerates heart 5. Stimulates EP and NE release 6. Stimulates gflucose release, 7. Inhibits stomach, pancrease, and intenstines, 8. Inhibits urination 9. Promotes ejaculation and vaginal contraction Describe the distribution of the sympathetic and parasympathetic distribution; sympathetic is concentrated at the sympathetic trunk, parasympathetic is concentrated at the cervical and sacral regions, the cervical vertebrae supply all the way from the eyes to the stomach, Describe the pathway of a sympathetic neuron starting at the intermedio lateral horn; preganglion neuron starts in the intermedio lateral horn and travels through the ventral horn out into the ventral root, the ventral root exits the vertebrae as it converges with the dorsal root to form the spinal nerve, it then travels through the white rami into the sympathetic chain where it can exit synpase and go through the gray rami, travel up the train and synapse there, or out through the splanchnic nerve and synpase in the peripheral ganglion Where are splanchic nerve found mostly; abdominal cavity Most targets of visceral motor nerves are dually innervated, which targets are not dually innervated; adrenal glands, sweat glands, and vascular smooth muscle What NT to cholinergic receptors respond to; ACHWhat are two types of cholinergic receptors; muscarinic and nicotinicWhat is the difference between the muscarinic and nicotinic NT; muscarinic are second messengers and nicotinic are ligand gated Adrenergic receptors respond to; NE or EPI (adrenaline), catecholamines What are the types of adrenergic rectpors; alpha and betaWhat type of receptors is alpha adrenergic; second messangerWhat type of receptors is beta adrenergic; second messenger How is ACH removed from a cleft; acetylcholinesteraseHow is NE removed from a cleft; broken down by monoamine oxidase (MAO) and catecholo-methyl transferase (COMT) Where are alpha 1 receptors found; smooth muscle in the blood vessels and visceral organs like the GI tractWhat is the primary action of alpha 1 receptors; vasoconstrictionWhat NTs do alpha 1 receptors respond to; EPI and NE equally Where are alpha 2 receptors found; presynaptic side What do alpha 2 receptors do; inhibit release of catecholamines for negative feedback regulation, causes vasodilation Where are beta 1 receptors found; heart What do beta 1 receptors do; increase rate and contractility What NT do beta 1 receptors respond to; EPI and NE equallyWhere are beta 2 receptors found; respiratory and uterine smooth muscle, GI smooth muscle, skeletal muscle blood vessels What do beta 2 receptors do; vasodilationWhat NT does beta 2 receptors respond to; EPI >>>>> NE What drugs block alpha 1 receptors; ‘zosins’What drugs block beta 2 receptors; propranololWhat drugs block beta 1 receptors; propranolol, atenolol, metoprololWhat drugs block ACH receptors; atropine What is the triad of Horner’s syndrome; ptosis, mitosis, anhydrosis What is mitosis; constrict What can cause Horner’s syndrome? Why?; a tumor at the sympathetic chain disrupts sympathetic nerve activity