Unit 1 Patho: Stress and ANS

homeostasis

level of constancy maintained in an organism

purpose of negative feedback

enable the body to adjust to levels and keep them in rang. WNL

sensory mechanisms

detect disruptions

control center

hypothalamus and brain stem, control v/s, reflexes, and neuroendocrine reactions

effector mechanism

acts to restore homeostasis

eustress

A positive stress that energizes a person and helps a person reach a goal

distress

negative stress

stressors can be

positive or negative, exogenous and endogenous, and physical or psychological

adaptive ability

how well an individual can allocate resources to manage a stressor

GAS

General Adaptation Syndrome

G in GAS

general: systemic reaction

A in GAS

adaptive: response to stress restores homeostasis

S in GAS

syndrome: involves multiple body systems

stages of gas

1. Alarm

2. Resistance

3. Exhaustion

alarm stage

The first stage of the general adaption syndrome, includes the fight or flight response (SYM NS)

HPA axis

Interaction between the nervous and endocrine systems to produce the body's response to stress. in alarm stage.

HPA axis includes

hypothalamus, pituitary gland, adrenal gland

Catacholamines

epinephrine and norepinephrine

Resistance

allocate resources where needed, selecting the most efficient defense mechanism. stress abates and PNS kicks in

exhaustion stage

the third stage of the GAS, characterized by weakened resistance and possible deterioration

McEwen

allostasis and allostatic load

Allostasis

ability to achieve stability through change, perception and our ability to react

allostatic load

wear and tear on the body caused by prolonged or excessive stress responses

activation of SNS stimulates

adrenal and pituitary gland

cns

brain and spinal cord

peripheral nervous system

somatic nervous system and autonomic nervous system

somatic nervous system

the division of the peripheral nervous system that controls the body's skeletal muscles

autonomic nervous system divided

sympathetic and parasympathetic

sympathetic

fight or flight

parasympathetic nervous system

rest and digest

Norepinephrine

sympathetic neurotransmitter, secreted by sympathetic post ganglionic nerve fibers, stimulates adrenergic receptors to produce fight or flight

acetylcholine

parasympathetic neurotransmitter, secreted by postganglionic parasympathetic nerve fibers to stimulate cholinergic receptors

two types of receptors

adrenergic and cholinergic

adrenergic receptors

receptor sites for the sympathetic neurotransmitters norepinephrine and epinephrine. stimulate fight or flight and inhibit rest and digest

adrenergic receptor types

alpha 1, alpha 2, beta 1, beta 2

Alpha 1 receptors location

located in sympathetic organs except the heart.

alpha 1 receptors effect

constrict bv and dilate pupils

alpha 2 receptor location

brain

Alpha 2 receptors

inhibit the release of more epinephrine

decrease symptoms flow, ONLY protection we have from unregulated sympathetic flow

Beta 1 receptors located

primarily in the heart, some in kidneys

beta 1 receptors do what

increase the rate and force of cardiac contraction, in kidneys they cause renin release raising bp

beta 2 receptors location

all sympathetic target organs but greatest use in lungs

beta 2 function

inhibit smooth muscle contraction causing vasodilation

cholinergic receptors

nicotinic and muscarinic

parasympathetic nervous system receptors

cholinergic receptors

muscarinic receptors

located in Parasympathetic target organs only, opp of all sam affects, stimulate peristalsis and secretion

nicotinic receptors

primarily stimulate somatic muscles, initiate voluntary smooth muscle movements, some located in ANS stimulating smooth muscles and glands

neurogenic shock

vasodilation, commonly occurring with spinal cord injury or damage to the medulla oblongata.

acute stress

triggers immediate fight or flight

chronic stress

long term; can be detrimental to health

body systems effected by chronic stress

cardiovascular, GI, immunity

cardiovascular risks from chronic stress

increased risk for stroke, heart attack, migraines

GI risks from chronic stress

stomach ulcers

Immunity risks from chronic stress

autoimmune diseases, increased sensitivity to disease

psychological effects from chronic stress

insomnia, fatigue, depression

neurogenic shock can be caused by

too much parasympathetic activity or not enough sympathetic activity

neurogenic shock causes a decrease in

vascular tone --> blood pressure --> systemic vascular resistance.

cardiac output, tissue perfusion, and cellular metabolism

hypovolemic shock

A condition in which low blood volume, due to massive internal or external bleeding or extensive loss of body water, results in inadequate perfusion.