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all heart cells capable of spontaneous depolarization
Hormone Chemical messengers, mostly those manufactured by the endocrine glands, thatare produced in one tissue and affect another
Tropic hormone hormone that stimulates the secretion of another hormone Target cell cell that has a receptor for a particular hormone Receptor on or in a cell, a specific protein to whose shape fits that of a specific molecularmessenger, such as a hormone
Hypophysectomy removal of the pituitary gland
Choose an answer 1 Hormone 2 primary hypercortisolism 3 Automatic cells 4 Hypophysectomy Don't know?
Ovariectomy surgical removal of one or both ovaries Thyroidectomy surgical removal of the thyroid gland Effects of thyroxine Elevates metabolic rate, increases resp. rate, increases heart rate, increasesalertness, stimulates growth hormone
Estrogen promotes bone growth Calcitonin promotes break down of bone and inhibits osteoclasts type 1 diabetes mellitus diabetes in which no beta-cell production of insulin occurs and the patient isdependent on insulin for survival
type 2 diabetes mellitus diabetes in which either the body produces insufficient insulin or insulin resistance(a defective use of the insulin that is produced) occurs; the patient usually is not dependent on insulin for survival primary hypercortisolism Cushing's syndrome secondary hypercortisolism Cushing's disease Primary adrenal insufficiency Addison's disease secondary adrenal insufficiency low cortisol, low ACTH Irritability ability to respond to a stimulus Conductivity the release of the neurotransmitter from the axon terminals of one neuron to thereceptors on the membrane of the next neuron
Nerve A bundle of nerve fibers Neuron nerve cell Cell body contains the cell nucleus, endoplasmic reticulum, Golgi apparatus, and most ofthe free ribosomes
Dendrites branch from the cell body & receive input from other neurons at specializedjunctions called synapses
Axon the branch that comes off the cell body & sends input to other neurons Trigger zone is more excitable than any other part of the soma or dendrites Axon hillock the site where the axon originates from the cell body Synapse a structure that permits a neuron to pass an electrical or chemical signal toanother neuron
After-hyperpolarization the membrane potential is even more negative than at rest as it approaches thepotassium equilibrium
Refractory period the period of reduced excitability Absolute refractory period span all of the depolarizations phase plus most the repolarization phase of anaction potential
Relative refractory period occurs immediately after the absolute refractory period and lasts approximately5-15 msec
Blood flow the amount of blood moving through tissue in a given period of time Blood pressure the force blood exerts against the wall of a vessel Peripheral resistance the resistance to blood flow provided by the vessels due to frictional forcedeveloped between the blood & the vessel
Pressure is _ proportional to flow directly Resistance is _ proportional to flow inversely Viscosity is _ proportional to resistance directly Length is _ proportional to resistance directly Radius is _ proportional to resistance indirectly Blood flow equation
Cardiac output the quantity of blood pumped from eh heart to the body per minute Stroke volume the volume of blood pumped from the heart each beat Diastole - the period when the ventricle is not contracting- passive ventricular filling
- artial systole Systole - the period of ventricular contraction- Isovolumic contraction
- Ventricular ejection Primary pumps ventricles End Diastolic Volume (EDV) volume of blood in each ventricle at end of ventricular diastole
Isovolumic contraction (also, isovolumetric contraction) initial phase of ventricular contraction in whichtension and pressure in the ventricle increase, but no blood is pumped or ejected from the heart End Systolic Volume (ESV) volume of blood remaining in each ventricle after systole Isovolumic relaxation - now all four valves are closed and the ventricles relax- while the atria have been filling with blood delivered form the lungs
- the atria pressure is now higher than the ventricles and this causes the mitralvalve to open and the diastolic filling begins
Effects of increasing vessel radius - pump rate increase- increased blood flow at a constant stroke volumffo incepre pgnisr stceEe
Effects of increasing stroke volume - decrease stroke rate- blood flow remains constant
Effects of increasing pump pressure - increase stroke rate- increase blood flow
Effects of decreasing chamber pressure - increase stroke rate- increase blood flow
Automatic cells all heart cells capable of spontaneous depolarization Automaticity The ability of the heart to generate and conduct electrical impulses on its own. Inward rectifiers ion flows freely in the inward direction through open channels, but not in theoutward direction
Chord Conductance Equation
Transient outward current one of the ion currents across the cell membrane of heart muscle cells. It is themain contributing current during the repolarizing phase 1 of the cardiac action potential Ca Influx At chemical synapses, the trigger for release of synaptic vesicles is K efflux The movement of potassium ions from guard cells to surrounding epidermis Effective refractory period The period after the firing of an impulse during which a cell may respond to astimulus but the response will not be passed along or continued as another impulse Compensatory pause the pause following an ectopic beat where the SA node is unaffected and thecadence of the heart is uninterrupted
Funny CAT Kept CALling K - Phase 4: If, ICaT, Ik- Phase 0: ICaL
