Bio 224 Lab Exam 1 Study Guide: Homeostasis & Blood Flow

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

• The text outlines essential concepts for a Bio 224 Lab Exam, covering topics from homeostasis to muscle physiology.

Lab 1: Homeostasis, Blood Flow, and Pressure

• Homeostasis is the process by which organisms maintain stable internal conditions despite external changes, including temperature and pH regulation.
• Negative feedback is a control mechanism where a change triggers a response that counteracts the initial change, maintaining homeostasis.
• The set-point represents the ideal range for a physiological variable, such as human body temperature of 37°C (98.6°F).
• Vasoconstriction is the narrowing of blood vessels, increasing blood pressure while reducing blood flow to certain areas, often due to cold or stress.
• Vasodilation is the widening of blood vessels, decreasing blood pressure while increasing blood flow to specific areas, often due to heat or metabolic activity.
• Local blood flow varies based on the metabolic needs of specific tissues or organs; during exercise, more blood is directed to muscles.
• Blood pressure measures the force exerted by circulation on blood vessel walls, measured in mmHg, expressed as systolic over diastolic pressure (e.g., 120/80 mmHg).
• Hypotension is abnormally low blood pressure, potentially causing dizziness or fainting, generally defined as a reading below 90/60 mmHg.
• Hypertension is abnormally high blood pressure, increasing the risk of heart disease and stroke, typically a reading of 130/80 mmHg or higher.
• A plethysmograph is a device used to measure volume changes within an organ or the entire body to assess blood flow or circulation.
• Thermoreceptors are sensory receptors that detect temperature changes, playing a crucial role in thermoregulation by signaling to the brain.

Blood Flow Pathway

• Blood is pumped from the left ventricle into the aorta
• The aorta is the largest artery in the body, branching 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, supplying the forearm and hand.
• Digital arteries, branching from palmar arches, supply blood to the fingertips.
• Blood returns from the fingertips through the digital veins.
• 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 from both sides merge into the superior vena cava.
• Blood enters the right atrium of the heart and then flows to the right ventricle.
• Blood is pumped from the right ventricle into the pulmonary arteries to the lungs 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 blood flow, while peripheral resistance influences central pressure.

Pulse Amplitude Regulation

• Pulse amplitude refers to the strength or intensity of the pulse felt in the arteries.
• Vasodilation increases blood flow to the periphery, leading to increased pulse amplitude.
• Increased pulse amplitude results from more blood volume in the arteries, making the pulse stronger.
• Vasoconstriction decreases blood flow to the periphery, leading to decreased pulse amplitude.
• Decreased pulse amplitude results from less blood volume in the arteries, making the pulse weaker.
• 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.
• Hormones like adrenaline can cause vasodilation or vasoconstriction.
• The sympathetic nervous system induces vasoconstriction, reducing pulse amplitude.
• The parasympathetic system promotes vasodilation, increasing pulse amplitude.
• Strong pulse may indicate good peripheral circulation and vasodilation.
• Weak pulse may suggest poor circulation, vasoconstriction, or other cardiovascular issues.
• Higher pulse amplitude indicates increased peripheral blood flow, while lower amplitude suggests reduced flow.

Vasoconstriction vs. Vasodilation

• Vasoconstriction decreases blood flow, increases blood pressure and helps conserve heat, reducing nutrient delivery.
• Vasodilation increases blood flow, decreases blood pressure, promotes heat loss, and enhances nutrient delivery.

Circulation from Left Ventricle to Fingertips

• The flow begins with oxygen-rich blood being pumped from the left ventricle into the aorta via the aortic valve.
• Blood enters the ascending aorta, then the aortic arch, and is distributed to the upper body and arms through major arteries.
• Blood travels through the subclavian artery, destined for the arms.
• The subclavian artery continues into the arm as the axillary artery in the armpit region.
• The axillary artery becomes the brachial artery running down the upper arm.
• The brachial artery then divides into the radial and ulnar arteries in the forearm.
• Blood reaches the fingertips through digital arteries branching off palmar arches.

Venous Return to Heart

• Deoxygenated blood from the fingertips flows back into the digital veins
• The digital veins converge into the palmar venous arches in the hand.
• Blood returns through the radial and ulnar veins, which then drain the forearm.
• The radial and ulnar veins merge and form the brachial vein, located in the upper arm.
• The brachial vein leads into the axillary vein, in the shoulder.
• The axillary vein becomes the subclavian vein, which carries blood from the arms towards the heart.
• The subclavian joins with the internal jugular vein to form the brachiocephalic vein.
• The left and right brachiocephalic veins merge to form the superior vena cava, returning deoxygenated blood to the heart.
• Blood from the superior vena cava enters the right atrium.
• Blood then moves through the tricuspid valve into the right ventricle.
• From the right ventricle, blood is pumped through the pulmonary valve into the pulmonary arteries, to the lungs for oxygenation.
• Oxygenated blood returns from the lungs via the pulmonary veins to the left atrium.
• Finally, blood flows from the left atrium through the mitral valve into the left ventricle, completing the circuit.

Vasodilation on Vessel Parameters

• Vasodilation reduces resistance within dilated vessels, increasing downstream blood flow.
• Vasodilation enhances the delivery of oxygen and nutrients to peripheral tissues.
• Increased blood flow supports tissue function, especially during exercise or high demand.
• Blood pressure decreases, since pressure is inversely related to vessel diameter.

Vasodilation Effects on Upstream Vessels

• The resistance decreases creating a situation where blood can flow more freely into the dilated region.
• It may slightly increase central pressure due to the increased volume of blood that moves more freely through the less resistant vessel.
• The heart adjusts heart rate and contractility, to stabilize overall systemic blood pressure.

Gravity’s Impact on Blood Flow

• Gravity has an influence on blood flow depending on body structure, circulation systems, and orientation.
• Humans and giraffes have unique adaptations to cope with gravity, unlike sharks, which experience minimal effects.

Blood Flow in Humans

• When standing or sitting, blood has to travel against gravity to return to the heart.
• Gravity pulls blood downward, increasing pressure in the veins of legs and feet.
• Venous valves and muscle contractions help to prevent backflow
• Standing still for long periods can lead to blood pooling in the legs, causing swelling or fainting.
• The head experiences less gravitational opposition as it is above the heart.
• Sudden drops in blood pressure can cause dizziness or fainting, since the blood fails to reach the brain efficiently.

Blood Flow in Sharks

• They remain relatively unaffected by gravity due to horizontal orientation.
• Due to buoyancy, blood distribution is equal.
• They don't need to pump blood against gravity so they do not have significant pressure differences.

Blood Flow in Giraffes

• Due to their large body that faces against gravity, the heart needs to build pressure to pump blood to the brain which leads to higher blood pressure
• Gravity assists the return of blood from the head to the heart.
• Thickened blood vessels and unique valve structures regulate pressure in lower extremities and when the head is lowered to drink.
• They also have a unique network of blood vessels (rete mirabile) at the base of the brain to regulate blood flow and prevent sudden blood rushes.

Lab 2: Nervous System Components

• Central Nervous System (CNS): The brain and spinal cord are its components and it processes sensory information and sends commands.
• Afferent Neuron: Carries sensory information from receptors to the central nervous system.
• Sensory Neuron: A subtype of afferent neuron that transfers any data from sensory receptors.
• Efferent Neuron: They carry commands from the CNS towards effector organs.
• Motor Neuron: A subtype of efferent neuron that carries impulses for the muscles contract.
• Interneuron: It connects sensory and motor neurons, and is complex for reasoning, memory, and decision-making.
• Reflex Arc: This controls response to a stimulus.
• Visuomotor learning: Adapting movements off visual feedback.
• Sensorimotor adaptation: Adjusting motor actions in response to changes.
• Prismatic adaptation: It is a form of sensorimotor adaptation when distorted by prisms.

Ascending Visual Pathway (Visual System)

• The visual pathway carry information from the eyes to the brain
• This begins from the retina, a layer of light-sensitive cells (rods and cones)
• Light converts electrical signal through the photoreceptors
• The electrical signals from the retina travel along the optic nerve
• The optic nerves cross the optic chiasm, fibers from the nasal side of each retina cross allowing binocular vision
• After the optic chiasm, the visual signals continue the optic tract, which leads it the thalamus.
• Visual information travels along optic radiations to the primary visual cortex (V1) where basic visual features are proceeded.

Ascending Auditory Pathway (Auditory System)

• The sounds transfers from the ear into the brain.
• Sound converts electrical signal in the cochlea
• The auditory nerve transmits from Vestibulocochlear to brainstem.
• Once the auditory nuclei synapse to superior olivary, sound is located among ear to ear signals.
• Ascends the lateral lemniscus to the midbrain.
• Processes information to to Inferior Colliculus.
• From the Colliculus the auditory signals are relayed by medial to the geniculate.
• Conveys sounds, tones to Auditory Cortex.

Descending Motor Pathway (Motor System)

• Transmits motor commands from brain to muscles.
• Proceeds down the corticospinal tract.
• Motor commands original in M1 in the frontal lobe
• Passes downwards by internal capsules.
• The fibers cross (decussate) the medulla.
• Lateral Corticospinal Tract: Controls limb movement.
• Anterior Corticospinal Tract: Primarily controls trunk muscles.

Factors for Speed of Response

• For auditory receptors the response is more faster; synapses are limited.
• For Visual receptors more longer.
• The neural Synapses introduce more delays in visual and slower.
• Sound stimulus creates rapid neural signals by receptors.

Sensory Receptor Activation

• Sound travels and is converted to signals almost at once.
• Light detectors requires light that requires more time.
• The visual requires more complex processes due light computation.

Auditory v Visual Attention

• Auditory attention is more effective as the brain can process without directly focus.
• Visual Needs more focus.

Neurophysiology of Prismatic Adaptation

• When prism distorts lateral view:
  • Neurons adjust for displacement.
  • Motor System fixes Muscle and accurate perception with signals.
• Neural Plasticity to reorganizes sensory recognition.

Sensory Adaptation

• Integration to maintain balance and vision.
• Provides rehab guidance and insights.

Sound Transmission

• Signals from air collects sounds that transmit them and guides.
• The canal converts into movement.
• Middle amplify signals from Inner structure.
• In the Organ of Corti, these translate signals.

Hair Cells

• Through their vibrations and movement for coding signals.

Sensory Processing

• Nerves travel into waves that transmit potentials.

Visual Anatomy

• Involves light that converts receptor signals of the eye.
• Light levels can tell cones of motions.
• Bipolar Cells form Synapses.
• The axons of ganglion form the optic nerve.
• At the base the nerves from both eyes is processed into hemisphere.
• Axons send to and signals to the Cortex.
• They convert light signals by signal processing that adapts.

Sensorimotor is:

• Adaptation to movement and spatial surroundings.
• Coordination to the Body.
• Is responsible for daily integration as well for strokes.

Lab-3: Sensory and Neural

• The definition of mechanoreceptor is that pressure receptors senses touch sensitivity. Examples include Pacinian corpuscles for deep pressure and Meissner’s corpuscles for light touch.
• Proprioceptor specializes position for balance of movement.
• Chordotonal Organ detect insects in limbs to balance vibrations.
• Mechanoreceptors are used for sensitive regulation.
• Neurons are transferred for electrical transmissions.
• All neuron signals send to the Nervous System.
• Sensory is the adaptation of neurons over time.

Location of Organs

• Organs exist on specific limbs for insects.

Functions of Organs

• Limbs and Joints allows for feedback with coordination.
• Vibration helps to allow movement of the sensory cells and balance.

Summary

• Sensory and the nervous relies on communication and coordination to maintain survival changes.

Adaptation

• Nerves adapt to new stimulus.

Sensation Adaptation:

• When there is energy/ stimulus, sensitivity adjusts to the new stimuli, and the body adapts its response.

Neural System:

• The nervous stimulus adjusts for all new circumstances.

Body and Muscles:

• Neurons react for balance of movement.

Experiment

• Adjust to heat- stimulus.

Population Coding

• This the effect with frequencies and groups.

Temporal Coding

• Action potential and coding relations.

Receptors

• Types that act to provide data.

Receptors

• Is where to measure a constant stimulus.

Encoding

• Prioritizes the nervous system and changes to the new.

Contras

This encodes the sensory.

Modulation

• Modulation in the neurotransmitters of new.

Coding's

• Utilizes data and functions.

Lab 4: Muscle Contraction and Physiology

• Tendons are used to transfer tissues movement over bones.
• Bundles are tissues and fibers.
• Fibers are used as myocyte and are contractions of muscle.
• Junctions transmit to each to control to activate muscles.
• Single is a functional unit that Innervates.
• Contractions occur by rapid release to stimuli.

Motor-units, etc

• Motor-unit recycles from contractions to increase force.

• Arc provides spinal movement.

• Pairs act/release movement simultaneously.

• The EMG is at the flat beginning with electric.

• When the EMG Spikes.

• Amplitudes will spike intensity levels.

• Action requires longer muscle.

• States happen where no action changes.

• Amplitudes find strength.

• Compare this between disorders, EMG results or nerves.

• During contractions.

Integration Steps

• If anything goes from muscles that analyze, is in order and are focus to prevent.

How action to muscles transfers as message

Motor Neuron generates potential, rapidly to send in charges.

• Action has axon that sends signal by Nerves/ Synapses
• Calcium allows synaptic activity to send chemicals from the synaptic vessels of the terminal.
• This contracts a neuron so ACh receptors to the protein send Sodium.
• Signals travel to membrane fibres to send out Calcium Ions.
• That is related through muscle action through Myosins.

Motor Unit

• Motor action.

Force

• Smaller actions, larger actions.
• Contractions have potential.

Action of potential.

• Neurons in muscles, has no rest.

Summary

Send signals through motor contraction depending.

Integrations

• Filaments move.

Steps:

• Structures for potential.
• Muscles for electrical signals.
• Signals for force in muscle-unit.

Contraction

• Fibers made with action and connection.
• Action occurs in release.
• Releases for power by myosin.
• That triggers the release.

Detachments

• Atp resets to be original.

Force

• Spikes will move and indicate change and will react, in all this process.

Summary

• Mechanism is activated through signal/ electrical processes.

Velocities of Functional Movements

• Transfer of movements
• Higher conduction is fast with stimulation
• Relays minimize response to signals.
• Saltatory movements allows for responses.
• This is awareness through faster reactions. That will treat any deactivating-illness.