LAB 3

define bradycardia

decrease in heart rate

the reduction of in cardiac output is usually attained through…

a decrease in heart rate (bradycardia)

define tachycardia

increase in heart rate

define vasodoliation

widening of blood vessel as a result of relaxation of the vascular smooth muscle; increase blood flow

define vasoconstriction

narrowing of a blood vessel as a result of contraction of the vascular smooth muscle; decrease blood flow

how does bradycardia and selective peripheral vasoconstriction serve as methods of oxygen conservation by diving vertebrate animals

during a forced or long dive, heart rate slows down, matching the circulatory demand

arterioles leading to the skeletal muscles, skin, kidneys, and gut constrict, shunting blood away from the muscles and other nonessential organs, and toward the heart ad brain

cardiovascular equation

MAP = CO x TPR

what is the relationship between CO, MAP and TR

the body varies CO andTPR to maintain MAP within very narrow boundaries

what does CO stand for

cardiac output

what does MAP stand for

mean arterial pressure

what does TPR stand for

total peripheral resistance

define cardiac output and how do you calculate it

volume of blood pumped per minute

heart rate x stroke volume

how does vasoconstriction affect total peripheral resistance, which in turn affects blood pressure

vasoconstriction INCREASES peripheral resistance to blood flow, INCREASES blood pressure

what is a baroreceptor

stretch-sensitive mechanoreceptor that is located in the walls of many the major blood vessels

explain the baroreceptor reflex

under normal conditions, the carotid and aortic baroreceptors fire a steady stream of action potentials, sending signals via primary afferent neurons to the CNS

cardiovascular control center in the medulla oblongata of the CNS integrates these inputs, and sends out efferent signals via automatic neurons that control heart rate, stroke volume, and vasomotor and venomotor tone, influencing blood pressure

increase in blood pressure causes walls of arteries to stretch → increase firing rate of baroreceptors → signals to decrease blood pressure

decrease in blood pressure causes walls of arteries to relax → decrease the firing rate of baroreceptor → signals to increase blood pressure

how does changes in heart rate and CO offset changes in blood pressure

CO varies in response to the changes in TPR in order to maintain MAP within. a narrow range

metabolic demand of the tissues is the ultimate regulator of the circulatory system

give examples of animals that exhibit strong diving reflex

sea turtles, penguins, seals

define stimuli

change in the environment

define interoceptor

internal receptors that detect changes within the environment of the environment of the body

define exteroreceptor

additional receptors that detect changes in the external environment

define sensory adaptation

action potential frequency often declines if the stimulus intensity is maintained at a constant level

define transduction

receptors detecting specific environmental changes and producing action potentials in a sensory neuron

define olfaction

detection of environmental chemicals from outside the body, the sense of smell

define gustation

detected of ingested chemicals, the sense of taste

define odorants

molecule that can be detected by the sense of smell

define tastants

chemicals that are detected by the sense of taste

define sensilla

a cuticular structure plus the associated chemoreceptor cells collectively

define olfactory sensilla

chemical enter via many pores

define gustatory sensilla

chemicals enter via a single pore

define contact chemoreception

the sense of taste involves direct contact with a substrate or object

define remote chemoreception

olfaction usually implies detection of compounds in gaseous form

where are olfactory sensilla found in invertebrate animals such as insects

most abundant on antennae, may also be found within mouthparts or external genitalia

where are gustatory sensilla found in invertebrate animals such as insects

most abundant in mouth parts, also found in; antennae, tarsi (legs), and genitalia

what was the hypothesis of the previous lab (insect chemosenses)

the chemoreceptors on the antennae are more important than those on the legs for the ability of individuals to locate food quickly and efficient