Vasodilation, Blood Flow & Gravity's Impact

Lab Study Guide for Exam 1 (Labs 1-4)

Lab 1

• Homeostasis is maintaining a stable internal environment, including temperature and pH, despite external changes.
• Negative feedback involves a response that counteracts an initial change to maintain homeostasis.
• The set-point is the ideal value or range for a physiological variable, such as 37°C for human body temperature.
• Vasoconstriction is the narrowing of blood vessels, increasing blood pressure and reducing blood flow to certain areas.
• Vasodilation is the widening of blood vessels, decreasing blood pressure and increasing blood flow to specific areas.
• Local blood flow is the distribution of blood to specific tissues or organs based on metabolic needs.
• Blood pressure is the force exerted by circulation on blood vessel walls, measured in mmHg as systolic over diastolic pressure.
• Hypotension is abnormally low blood pressure, which may cause dizziness or shock, generally below 90/60 mmHg.
• Hypertension is abnormally high blood pressure, increasing heart disease and stroke risk, generally above 130/80 mmHg.
• A plethysmograph measures changes in volume within an organ or body to assess blood flow.
• Thermoreceptors are sensory receptors that detect temperature changes to maintain body temperature.

Path of Blood Flow from Left Ventricle to Fingertips and Back

• Blood flows from the left ventricle into the aorta.
• The aorta branches into smaller arteries.
• Blood flows into the subclavian artery, which supplies the arms.
• The subclavian artery becomes the brachial artery as it travels down the arm.
• The brachial artery splits into the radial and ulnar arteries in the forearm, supplying blood to the hand.
• The digital arteries supply blood to the fingertips.
• Blood returns from the fingertips through the digital veins.
• The digital veins merge into the ulnar and radial veins.
• The ulnar and radial veins combine to form the brachial vein.
• The brachial vein drains into the subclavian vein.
• The subclavian vein joins with the internal jugular vein to form the brachiocephalic vein.
• The brachiocephalic veins merge into the superior vena cava.
• Blood enters the right atrium of the heart.
• Blood flows from the right atrium to the right ventricle.
• Blood is pumped from the right ventricle into the pulmonary arteries for oxygenation.
• Oxygenated blood returns to the left atrium via the pulmonary veins.
• Blood flows from the left atrium to the left ventricle, completing the circuit.
• Central blood pressure drives peripheral blood flow, while peripheral resistance influences central pressure.

Pulse Amplitude

• Pulse amplitude is the strength/intensity of the pulse felt in arteries, influenced by blood volume pumped.
• Vasodilation increases peripheral blood flow, leading to increased pulse amplitude.
• Vasoconstriction decreases peripheral blood flow, leading to decreased pulse amplitude.

Factors influencing Peripheral Blood Flow

• Heat causes vasodilation, increasing blood flow and pulse amplitude.
• Cold causes vasoconstriction, decreasing blood flow and pulse amplitude.
• Exercise causes vasodilation in active muscles, increasing blood flow and pulse amplitude.
• Adrenaline can affect blood flow/pulse amplitude.
• Autonomic nervous system sympathetic induces vasoconstriction and parasympathetic promotes vasodialtion.
• A higher pulse amplitude indicates increased peripheral blood flow, and a lower amplitude suggests reduced flow.

Vasoconstriction vs Vasodilation

• Vasoconstriction decreases blood flow and pulse amplitude, while increasing blood pressure and conserving heat.
• Vasodilation increases blood flow and pulse amplitude, while decreasing blood pressure, promoting heat loss, and improving oxygen delivery.

Path of Blood Flow during a Complete Blood Flow

• From the left ventricle, oxygen-rich blood is pumped into the aorta through the aortic valve.
• Blood enters the ascending aorta and passes through the aortic arch, distributing to the upper body and arms via major arteries.
• Blood flows to the sublavian artery and into to the axillary artery.
• The axillary artery becomes the brachial artery.
• For the forearm the Brachial artery divides into the radial and ulnar arteries.
• Arteries further divide into smaller branches, forming the superficial and deep palmar arches in the hand.
• Blood reaches the fingertips through the digital arteries, branches off the palmar arches.
• Deoxygenated blood from the digital veins drains in the digital veins.
• Digital veins converge into the palmar venous.
• Ulnar veins and radial veins merge to form the brachial veins.
• Brachial veins continues as the axillary vein in the shouder region.
• The Axillary veins then become the subclavian.
• Then joins with the internal jugular to for the brachio cephalic.
• The left and right brachiocephalic veins merge to form the superior vena cava, back to the heart.
• Blood enters with the right atrium, through the tricuspid valve into the right ventricle.
• The pulmonary arteries and goes to the lungs for oxygenation.
• O2 rich blood returns from the pulmonary veins.
• From the left atrium moves through the mitrial valve in to the left ventricle.

Vasodilation Effects

• Vasodilation reduces resistance, increasing blood flow downstream.
• It generally does not significantly change the change or may slightly increase blood pressure in the central vessels.
• The body uses vasodilation to ensure tissues needing more oxygen, like muscles increase blood flow.

Gravity on Blood Flow between Species

• Gravity affects blood flow to/from lower limbs due to the need to pump against it for venous return, humans have veinous valves.
• Blood flow to the head experiences less gravitational opposition and assistance with return.
• Sharks have more even blood distribution.
• To survive the pressures Giraffes need high systolic blood pressure due to tall body so they can maintain blood supply to the brain.
• Giraffes thickened blood vessels and unique valve structures help avoid blood pooling in lower extremities and Reta Mirabile(veins) regulate regulating blood flow to the brain.

Lab 2

• The central nervous system (CNS) consists of the brain and spinal cord
• The primary control center for processing and interpreting sensory information and sending out commands.
• An afferent neuron carries sensory receptors from the CNS.
• A sensory neuron is a type of afferent neuron that carries information to the nervous system.
• Efferent neuron carries commands away to effector organs.
• A motor neuron is a type of efferent that carries impulses to the muscles.
• Interneuron connects (afferent ) sensory and (efferent) motor within the CNS.
• A reflex arc is a netral that controls involuntary response.
• Visuomotor learning coordinates visual info with motor actions by adapting movenments.
• Sensorimotor adaptation adjusts actions with environmental changes.
• Prismatic adaptation occurs when visual input is distored by prisms and the brain adatps to coordinate accurate movements.

Ascending Visual Pathway

• The Visual Pathway carries from the eyes to the brain.
• The pathway begins in the retina a layer of light sensitive cells.
• These receptors convert light into electrical signals.
• These travel along the optic nerve.
• At the optic chiasm, fibers from the nasal side of each cross to the opposite where as the fibers on the temporal side remain on the same side.
• Allowing the visual to continue down the optic tract and to the the lateral geniculate nucleus(LGN).
• The LGN relays to the to the visual cortex and these connect to the v1 visual cortex to be sent to higher visual areas after such as recognition.

Ascending Auditory Pathway

• Carries sound infor from ears to brain for processing.
• Sound waves become electric signals in the cochlea.
• Those signals are conducted by the the auditory nerve branches from the vestibulocochlear nerve) in the brainstem.
• Auditory nerve Fibers first synapse in the cochlea Nuclei.
• Some signal travel to S.O.C involved in sound localization.
• Ascends to the inferior colliculus in the mid brain via the lateral lemniscus, where its processed for sound.
• Then transferred to the M.G.N media geniculate nucleus in the thamulus station were info is relayed.
• A.C auditory cotex.

Descending Motor Pathway

• It carries Commands from the brain t body for movement.
• Motor cortex M1 that commands orginate in the frontal lobe area is responsible for planning.
• Where it travels down a bundle of white nerves that connect with the brain stem and the spinal cord

Reaction Time

• Reaction times for auditory is faster.
• The path for auditory is shorter leading to faster processing and little steps.
• Sound waves quickly transduced and travel via the auditory nerve to brainstem inferior collicus MGN of thamus leading to corex requiring processing.
• Visuals more complex needing brain greater to process color shape movements ,travel through a longer path.

Prismatic Adaptation

• Prismatic happens with shift of vision.
• A Neural adaptation where the brain interprets the distorted input over time where it is percieved and compensates.

Auditory Pathway Anatomy

• Outer that collects and directs sound waves done by pinna
• The Tube for sound called the ext auditory.
• MIddle were vibrating leads the the tympanic embrance Vibrates and turns into vibrations.
• Where it uses ossicles and amplify into the inner.
• Spiral fluid build structure named cochlea.
• The Specialized sensory receptor Hair cells produce hair like projection.
• Basilar membrane vibrates from frequencies.
• Where elctircal goes to the auditoral that carries it to the brain stem.
• Where the first relay station it encounters is the cochlear Nucleis.
• 6.Involved the thalamic station for sensory information ,and forwards the auditory cortex.
• Locates is the top lobe and its involved the auditory for the interpetion of pitch, volume, sound and Rythem.
• Transduction when vibrations are converted into energy through mechanical transmissions
• Where k+ potsium rushes in for potential.

Visual Pathway Anatomy

• Back of the tissue called retnia.
• That has photoreceptors
• Which types rods (low light) cones ( function bright and responsible for all Color.
• Where Photrreceptors synapse into bipolar sends intermedery ganglion.
• Ganglion axons form what make the opitic vision so responsible can trasnit of vison.
• LGN thamaus sends visual there.
• Visual cotext V1 of brain interperets like color shapes.

Lab 3

• Mechanoreceptor responds to pressure.
• Propriocepter helps infodm body position.
• Chorodtional Oragn helps detect vibes.
• Stretch receptors like regulating.
• Nerve transmitts.
• Afferent info from central to neurons.
• Sensory is constant simuli over time.

Chordotonal Organ in Cockroaches

• Detect joints around the body to maintan balance and coordination.
• Composed unit is Scolopidia ,it contians scolopae and a membrane that deformatiom.
• Which Allows the feed back and to the provide movement balance coordanatiom and helps with touch.
• Organ which there the specialized which includes sensilla Tension is what helps to detect exoskeleon flex is a part.

Chordotonal Oragan Hexapods

• Located joint its help provide adjust movement.
• and into system. for movemen with contrictuions it provides and helps mainatian poster balance with reflex the actions.

Frequency Coding

• Neurons are rate faster as they stronger lower weaker.
• Frequency can show can convevy the strentgth of the stmiuli.
• Tempral helps to convey multi.

Sensory Adaption

• Animals help them adjust.
• helps the animal focus.
• Energy Conservation save energy by non responsive ones.
• Allow animal to read and know is around in enviro.

Lab 4

• Tendons connective.
• The muscles are grouped tissue -Bundle
• A single fiber responsible for contract fiber.
• Neuro junction transfer neurons.
• Recuritment activates more fibers.
• Spinal Pathway for actions its stimuations that will allows nerves will contract motor
• Extenson muscles.
• Flexcor muscles bend.
• Basline minimal electrical activity from nerves in at the muscles
• The hight reflects on the muscles higher stronger contraction.

Steps

1. The basic electrical Activity
2. Spike activities begin
3. Strength of spike
4. If consistancy is there

Elactirc Singlas

• Genereates potentials by infux of Na
• Potential reach through nerve and the channel leads release.
• Contraction goes calcium to contract.
• The amount of fibers helps amount muscle of move.

Models

• Muscle consist sarcomeres and thin flimanets.
• Contract when thickthin flilamenets and interacte heads

  • Generate Action is the process stimulates of musles to create actio

  • Ach released which create action.

  • and the increase for calcium by actin.

  • Then attach to head power to pull flimarents and contract

• -By Spatial multi neurons can contract or single can contrcat.

Spnial Flex

• That start strech receptor. -The sensory to spnia coloum nerve and center which responds back will react for that reasong.

Chordition of limb

• Is integrate help tuning in muscles. -helps is adjust the position of tones.

Cordination

-helps integration will musclesto and prevents exceesie muscle is allows contrcaions.

Conduction Velodity is that

-Its faster and allow quicke process action -The myelin helps quicker and fattty cells.

• Pathological is caused because nerves and disease can causes slow.
• and adaption of the different in that allows the muscle adjust.

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Explore vasodilation's effects on blood flow and pressure in different body regions. Understand how gravity affects circulation, especially in extremities and the challenges it poses. Compare circulatory adaptations in humans versus giraffes.