ANFS 345: Exam 1

Physiology and the Environment, Nervous System

Physiology

Physiology

study of the functions and mechanisms in a living system, typically divided by organ system

Levels of Physiology Organization

evolutionary, ecological, cellular/tissue, biochemical/molecular

Types of Changes

acute, chronic, evolutionary, developmental, periodic

Acute Changes

short term, soon after an environment change, reversible

Chronic Changes

long term, some time after an environment change, reversible

Evolutionary Changes

alteration of gene frequencies over generations

Developmental Changes

changes from conception to adulthood

Periodic Changes

changes in repeating patterns, originating from internal biological clock

Types of Environmental Stimuli

local, distant, biological, chemical, physical

Organ Interactions with Environment

all organs are constantly interacting to different degrees, not all organs respond equally to a given stimulus

Homeostasis

state of normal function that organs try to maintain through compensatory mechanisms

Pathophysiology

result of the inability to maintain homeostasis in organs or organ systems

Environmental Physiology Examples

pheasant, salmon, firefly

Pheasant Evolutionary Context

prey for foxes, must be able to successfully escape in order to live and reproduce

Pheasant Cellular Context

muscular system is designed for short bursts to escape a fox, foxes are designed for long runs

Pheasant Biochemical Context

the krebs cycle is necessary for ATP production which determines how fast the pheasant can escape

Salmon Evolutionary Context

different up and downstream variants evolve separately with larger genetic differences generally found with larger distances

Salmon Chemical/Physics Context

abilities controlled by thrust - drag = force x acceleration and cellular respiration to produce energy

Salmon Physiological Context

depends on all levels of organization, cellular physiology, organ physiology, biochemistry, morphology, biomechanics

Salmon Ecological Context

water type has influence over membrane proteins and ease of spawning ground access has influence over ovary size

Firefly Light Production

produce light for different reasons and in varying patterns depending on type

Firefly Light Anatomy

gas filled tubule brings O2 to light cells, branching system with <1um diameter terminal tubules

Firefly Light Chemistry

luciferin + ATP -> luciferyl-AMP, luciferyl-AMP + O2 -> excited electrons, excited electrons release photons when returning to ground state

Firefly Light Control

mitochondria intercept O2 in dark state, nervous system produces nitric oxide which block mitochondria and allow O2 to reach luciferin in flashing state

Central Nervous System Anatomy

brain and spinal cord

Central Nervous System Function

central control center, any process regarding learning

Peripheral Nervous System Anatomy

cranial and spinal nerves

Peripheral Nervous System Classifications

somatic and autonomic nervous system

Somatic Nervous System

voluntary control

Autonomic Nervous System

involuntary control, fight or flight

Nervous System Classification

central or peripheral

Cranial Nerves

12 paired nerves originating from the brain and brainstem, (10s in vertebrates)

Spinal Nerves

31 paired nerves originating from the spinal cord, (30s in vertebrates)

Ganglia

clusters of cell bodies in PNS

Neurons

nerve cells

Glial Cells

non synaptic support cells

Brain Anatomy

forebrain, midbrain, hindbrain, protected by the cranium

Forebrain Anatomy

cerebrum, hypothalamus, thalamus

Midbrain Anatomy

midbrain

Hindbrain Anatomy

pons, medulla, cerebellum

Brainstem Anatomy

midbrain, pons, medulla, connects cerebrum/cerebellum to spinal cord

Cerebrum Function

voluntary, touch, vision, hearing, speech, reasoning, emotions, learning, fine motor control

Brainstem Function

involuntary, relay center, breathing, heart rate, temperature, wake sleep cycles, digestion, sneezing, coughing, vomiting, swallowing

Cerebellum Function

involuntary (affected by alcohol), muscle movements, posture, balance

Neuron Function

take up and transmit information

Neuron Components

dendrite, soma, nucleus, axon, myelin sheath, axon terminal, axon hillock, node of ranvier, schwann cell

Dendrite

receives signals from other neurons, branching portion

Soma

cell body, organizes and keeps cell functional

Nucleus

control center of the neuron

Axon

long extension of neuron that carries signal

Myelin Sheath

wraps around axon in some neurons, increases speed of signal

Axon Terminal

forms junction with other cells

Axon Hillock

generates impulse, junction between soma and axon

Node of Ranvier

allows diffusion of ions

Schwann Cell

produces myelin sheath

Afferent Neuron

sensory, information into the CNS via dorsal root

Efferent Neuron

motor, information away from the CNS via ventral root

Interneuron

relay neuron, carries information from afferent to efferent neurons in the spinal cord

Reflex Arc

stimulus and involuntary response

Reflex Arc Pathway

stimulus -> afferent system -> spinal cord -> efferent system -> response

Neural Synapse Pathway

pre-synaptic neuron sending action potential through synapse to post-synaptic neuron

Synaptic Transmission Steps

action potential depolarizes axon terminal membrane, voltage gated Ca2+ channels open and Ca2+ flows in, Ca2+ triggers synaptic vesicles to release neurotransmitters, neurotransmitters bind to receptors on target cell, receptors allow positive ions to flow in

Action Potential Path

axon hillock -> axon -> axon terminal

Action Potential in Terminal Triggers

depolarization of the pre-synaptic axon terminal membrane

Depolarization of Membrane Triggers

voltage gated calcium channels to open

Calcium Channels Opening Triggers

calcium to flow into the axon terminal from the synaptic cleft

Calcium Flow in Triggers

synaptic vesicles to fuse to the membrane and release neurotransmitters

Neurotransmitter in Synapses

acetylcholine, ACH

ACH Release Triggers

ACH binding to ligand gated channels on the post synaptic membrane

ACH Binding Triggers

ligand gated channels to open and allow positive ions (sodium) to flow in

Leftover ACH in Synaptic Cleft Triggers

acetylcholinesterase breaks down leftover ACH

Chemicals Involved in Action Potential Transfer

calcium, acetylcholine, sodium

Neuromuscular Junction

contact between motor neuron and skeletal muscle cell, sodium generates action potential in the muscle to contract

Stress Negatives

manifests as restlessness, irritability, overwhelmed, isolation

Stress Positives

allows for energy and focus

Chronic Stress Changes

high cortisol increases connections in the amygdala and decreases connections in the hippocampus

HPA Axis

hypothalamus, pituitary gland, adrenal glands, cortisol is the main stress hormone

Cortisol

main stress hormone

Hypothalamus Control

body temperature, hunger, fatigue, sleep

Basal Ganglia Control

movement and learning

Thalamus Control

sleep and consciousness

Amygdala Control

memory, decision making, emotional response, fear center

Hippocampus Control

memory formation, navigation, learning, stress control

Effects of Chronic Elevated Cortisol

hippocampus cannot make new connections, ability to control stress decreases, prefrontal cortex shrinks, harder to learn and remember, may lead to alzheimers or depression

Types of Memory

short term, long term

Short Term Memory Location

specifics unknown, probably related to prefrontal cortex

Long Term Memory Location

hippocampus and other areas

Long Term Potentiation

when 2 neurons communicate repeatedly the efficiency of communication increases, increased myelination increases speed

Mechanisms of Forgetting

age, brain shrinking, use it or lose it, lower levels of ACH, reduced memory making abilities, low serotonin

Physical Effects of Stress

headache, increased depression, heartburn, insomnia, rapid breathing, weakened immune system, risk of heart attack high blood sugar, pounding heart, high blood pressure, fertility problems, stomachache, erectile dysfunction, low sex drive, missed periods, tense muscles

Headache

stress triggers and intensifies tension headaches

Increased Depression

constant stress is emotionally draining

Heartburn

stress increases stomach acid production which can cause irritation

Insomnia

stress makes it harder to fall asleep and stay asleep

Rapid Breathing

stress causes the muscles that help with breathing to tense up, making people feel short of breath

Weakened Immune System

stress can long term reduce immune function

Heart Attack Risk

long term increased heart rate and blood pressure can weaken arteries

High Blood Sugar

stress causes the liver to release more glucose, increase risk for type II diabetes

Pounding Heart

stress increases heart rate to increase blood flow to limbs and vital organs

High Blood Pressure

cortisol can tighten blood vessels and therefore raise bp