Homeostasis and Blood Pressure

Lab 1 Summary:

• Homeostasis is the process of maintaining a stable internal environment in a living organism, including temperature and pH regulation.
• Negative feedback is a control mechanism counteracting changes to maintain homeostasis (e.g., cooling the body when temperature rises).
• The set-point is the ideal range that the body tries to maintain (e.g., 37°C for human body temperature).
• Vasoconstriction narrows blood vessels, increasing blood pressure and reducing flow to certain areas, occurs in response to cold or stress.
• Vasodilation widens blood vessels, decreasing blood pressure and increasing flow to specific areas, occurs in response to heat or increased metabolism.
• Local blood flow is the distribution of blood to specific tissues or organs based on metabolic needs.
• Blood pressure is the force of circulating blood on blood vessel walls, measured in mmHg (e.g., 120/80 mmHg).
• Hypotension is abnormally low blood pressure (below 90/60 mmHg), potentially causing dizziness or fainting.
• Hypertension is abnormally high blood pressure (130/80 mmHg or higher).
• A plethysmograph measures volume changes in an organ or the body to assess blood flow.
• Thermoreceptors are sensory receptors detecting temperature changes that aid thermoregulation.

Blood Flow

• Blood flows from the left ventricle to the aorta.
• The aorta (the body's largest artery) branches into smaller arteries.
• Blood enters the subclavian artery, supplying the arms.
• Next, blood flows into the brachial artery as it travels into the arm.
• In the forearm, the brachial artery splits into radial and ulnar arteries for the forearm and hand.
• Blood flows into the digital arteries, the terminal branches that supply the fingertips.
• From the fingertips, blood returns to the digital veins.
• Digital veins converge into ulnar and radial veins.
• The ulnar and radial veins merge to form the brachial vein.
• The brachial vein drains into the subclavian vein.
• The subclavian vein joins the internal jugular vein to form the brachiocephalic vein.
• Brachiocephalic veins from both sides merge into the superior vena cava.
• Blood enters the right atrium from the superior vena cava.
• Blood flows from the right atrium to the right ventricle.
• The right ventricle pumps blood 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 blood flow to the peripheries.
• Peripheral resistance influences the central blood pressure needed to maintain flow.

Pulse Amplitude

• Pulse amplitude reflects the strength or intensity of arterial pulse.
• It is influenced by the volume of blood being pumped.
• Vasodilation increases blood flow to the periphery, resulting in increased pulse amplitude.
• Vasoconstriction decreases blood flow to the periphery, resulting in a decreased pulse amplitude.
• 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, affecting blood flow and pulse amplitude.
• 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 or vasoconstriction.
• Vasoconstriction reduces peripheral blood flow and raises blood pressure to conserve heat.
• Vasodilation increases peripheral blood flow and lowers blood pressure, promoting heat loss.

Blood Flow & Gravity

• Gravity significantly affects blood flow, especially in upright animals.
• Gravity increases pressure in lower limb veins, requiring venous valves and muscle pumps to aid venous return.
• Blood flow to the head experiences less gravitational opposition.
• Blood pressure is generally lower in the head due to less opposing gravitational force.
• Sharks are less affected by gravity owing to horizontal orientation within a buoyant aquatic system.
• Giraffes require high blood pressure and specialized vascular adaptations to pump blood to the brain.
• Rete mirabile is present at the base of a giraffe's brain to regulate blood flow during head movements.

Lab 2 Summary: The Nervous System

Definitions of Terms:

• The central nervous system (CNS) includes the brain and spinal cord.
• The CNS processes sensory information then coordinates voluntary and involuntary bodily responses.
• An afferent neuron transmits sensory information from receptors to the CNS.
• A sensory neuron is an afferent neuron specialized to carry information from sensory receptors to the CNS.
• An efferent neuron transmits signals from the CNS to effector organs (muscles/glands).
• A motor neuron is an efferent neuron specialized to carry impulses from the CNS to muscles.
• The impulse from CNS causes muscle contraction.
• An interneuron connects afferent and efferent neurons within the CNS.
• Interneurons process information for reflexes and higher-level functions.
• A reflex arc is a neural pathway for immediate involuntary responses consisting of sensory, and motor neurons.
• Visuomotor learning coordinates visual information with motor actions.
• It involves adapting movements based on visual feedback.
• Sensorimotor adaptation adjusts motor actions responding to changes in sensory input or environment.
• Prismatic adaptation is correcting to visual input distorted by prisms with visual input and motor actions.

Ascending Pathways:

• The visual pathway begins in the retina of the eye.
• Photoreceptors convert light to electrical signals.
• Optic nerve transmits signals to the brain.
• Optic chiasm allows visual information from both eyes to be processed.
• Optic tract carries signals to the lateral geniculate nucleus (LGN).
• LGN relays signals to the visual cortex (V1).
• Visual cortex processes visual features.
• The auditory pathway starts at the cochlea of the inner ear, where hair cells convert sound to lectrical signals.
• The auditory nerve (vestibulocochlear nerve) transmits signals to the brainstem>
• Signals travel to the superior olivary complex, then lateral lemniscus, to the inferior colliculus in midbrain.
• The medial geniculate nucleus (MGN) relays signals to the auditory cortex.
• The auditory cortex processes sound frequencies and loudness.

Descending Pathways

• The descending motor pathway carries motor commands from the brain to the muscles.
• M1 (in the frontal lobe) initiates voluntary movements.
• Signals travel to the brainstem and spinal cord to corticospinal tract.
• Most corticospinal tract fibers decussate (cross over) in the medulla, forming the lateral corticospinal tract.
• Descending nerve fibers then synapse onto lower motor neurons in the spinal cord.
• Lower motor neurons innervate muscles.

Reaction Times

• Auditory cues are processed (140-160 milliseconds) faster due to auditory pathways having fewer synapses.
• Visual cues are processed (180-200 milliseconds) more slowly, owing to the complex detailed spatial information.
• Auditory stimuli travel sound waves directly and have a shorter neural pathway.
• Humans passively detect and respond faster to auditory cues.

Prismatic Adaptation

• Light enters the eye and stimulates photoreceptors
• Signals are transmitted via the optic nerve to the visual cortex
• Prisms shift the visual field, causing a mismatch between perceived and actual location
• Over time, the visual system begins to adapt to this new input
• Neurons adjust firing patterns to compensate and allow to recalibrate spatial relationships

Significance of Prismatic Adaptation

• Prismatic adaptation exemplifies neural plasticity.
• It highlights the brain's ability to reorganize and adapt to new sensory information.
• Neural plasticity is essential for learning and recovery from injuries
• Demonstrates how nervous system integrates visual and motor information

Auditory Pathway Anatomy

• Outer ear collects sound waves that travel to the eardrum
• The middle ear includes eardrum and ossicles
• Eardrum converts sound waves into mechanical vibrations
• Ossicles amplify and transmit vibrations to inner ear
• The inner ear or cochlea contains sensory and hearing organs
• Basilar membrane vibrates and hair cells open ion channels
• Nerve electrical signals travel by auditory nerve to brain

Retina Anatomy

• Human retina containing photoreceptor coverts light to visual signals via phototransduction
• Bipolar cells process electrical signals and are intermediaries for ganglion
• Axons of Ganglion cells responsible for transmitting visual
• Optical nerve signals carry visual via to the disk

Sensory Adaption

• Sensory adaptation occurs from the receptors being less sensitive long therm
• Focus occurs on what is most important, also conserved energy and memory
• With temperature adjustment can occur in skin and touch, allowing for rapid adaption

Muscle

• Muscle spendal indicates length where
• Holgi is too large if a potential occurs
• It can respond to long

Lab 3 Definitions:

• Mechanoreceptors respond to mechanical pressure/distortion, vibration, and sound.
• Proprioceptors provide information about body position, movement, and muscle tension
• Chordotonal organs in invertebrates detect mechanical changes.
• Stretch receptors respond to the stretching of tissues.
• Nerves transmit electrical signals between the central nervous system (CNS).
• Afferent neurons transmit sensory information from peripheral sensory receptors to the CNS.
• Sensory adaptation: sensory receptors become less sensitive to constant stimuli over time.

Chordotonal Organs

• Found in cockroach legs and abdoman
• Detects changes in movement tension
• Functional role of feedback to allow balance
• Are sensitive to vibration

Frequency Coding

• Found around joints
• They sent information by moving feet and legs
• This enables integration
• The role happens where you can more

Adaption

• Is a method to filter and concentrate on new environments

Muscle Spinals

• A key component
• Provides direct central feedback which involves the brain

Leg

• They detect how chordal is connected
• Provide feed back on a posture base

Leg Functions

• Provide chordal for feedback
• Connects balance and more

Chordal

• Complex sensory

4.4

• Velocity is total meters per second
• Synaptic speed
• Follows to the neuron What is motor unit ? What is tetanus?

Terms and Definitions

• A tendon connects muscles to bones and transmits the force, supporting action.
• Muscle Bundles: are groups muscle cells and bundled structures
• Muscle Fibers: A single fiber makes capable of contracting
• There is a connection when the neuron can simulate contraction
• The system provides signal which will stimulate eachother
• This provides connection of all unit

What is Twitch

• Action potential from neurone and relaxation

Tetanus

• Is sustained muscle with high stimulation

Motor Unit

• additional will stimulate when and where need to push the increase

What is the reflex arc?

• pathway stimulation is short and fast

Action Potential

• Has generate due to sodium

Action

• Ach transmits muscle fibres

Electrical

• electrical activates

Motor

Action potential releases neuron transmitters It increases Frequency stimulates Size action is dependent Coordination ensure smoofht stimulation

Sliding

• Electrical is
• Calcium is

Sarcomere

• Sarcomere

Sarc

• Calicum connect then they are at the top of this all together
• If it is constant then the rate is high

Sumary

Conduction affects the movement