Homeostasis (Autonomic Reflexes)

homeostasis

the tendency of organisms to regulate and maintain relative internal stability

Afferent

integrating

efferent

The components of the homeostatic reflex include an __________ pathway from the receptor/sensor that goes to an __________ center in the CNS and then projects to an ________ pathway that goes to the effector

Stressor/stimulus

afferent

what generally causes an imbalance of homeostasis? Does the imbalance come from the afferent or efferent side?

Response/feedback

efferent

what generally corrects can imbalance of homeostasis? Does the correction come from the afferent or efferent side?

Positive feedback

negative feedback

what are the two types of responses/feedbacks that can be provided via the efferent pathway?

Amplified

starting

with positive feedback, the imbalance is __________. The system may end up far from its _________ point before homeostasis occurs (usually because rapid change is needed)

Pregnancy contractions

blood clotting

what are two examples of positive feedback?

irritation or stretch of cervix

hypothalamus

oxytocin release

increase uterine muscle contraction (fergunson reflex)

when baby is born

What is the stimulus for pregnancy contractions? Where does the signal go specifically? What is the positive feedback element? What is the response? when does the system go back to normal?

receptors

counteract

set point

With negative feedback, an imbalance changes the internal environment which is detected by __________ and corrective measures are activated to _____________ the change back toward the ____ ______

Pressure

temperature

pH

There are many examples of negative feedback but provide a few here

Homeothermic animals

what type of animals are Physiological capable of maintaining a constant core body temperature with minimal deviation from the setpoint

Poikilothermic animals

what type of animals need to adopt behavioral strategies to regulate body temperature?

Mammals and birds (endotherms, warm blooded animals)

what are examples of homeothermic animals?

Fish, reptiles, amphibians (ectotherms, cold-blooded animals)

what are examples of poikothermic animals?

Temperature

thermoreceptors

hypothalamus

autonomic

somatomotor

The regulatory circuit for core body temperature is roughly:

stimulus: changes in ___________

inputs: peripheral and central ______________

Inputs are sent to the thermoregulator: _____________

outputs: ___________ and ___________ systems

Sympathetic

skin

blood

piloerector

brown adipose

With cold ambient temperature the autonomic response includes increased (choose one: sympathetic/parasymapthetic) activity to the ____ and _______ vessels as well as to ____________ muscles And to _______ _________ tissue

vasoconstrction

conservation

With cold ambient temperatures, what does increased sympathetic activity to the skin and blood vessels cause? This aids in heat (choose one: production/conservation)

Skin insulation

conservation

With cold ambient temperatures, what does increased sympathetic activity to the Piloerector cause? This aids in heat (choose one: production/conservation)

increased metabolic activity

production

With cold ambient temperatures, what does increased sympathetic activity to brown adipose tissue cause? This aids in heat (choose one: production/conservation)

skeletal muscle

shivering

With cold ambient temperature the somatomotor response includes increased activity to _______ __________ motor neurons which causes ____________

Increased metabolic activity

production

With cold ambient temperatures, what does increased somatomotor activity to skeletal muscle leading to shivering cause? This aids in heat (choose one: production/conservation)

sympathetic

skin

blood

Brown adipose

sweat glands

With hot ambient temperature the autonomic response includes DECREASED (choose one: sympathetic/parasymapthetic) activity to the ____ and _______ vessels as well as to _______ _________ tissue and INCREASED activity to _______ _______

vasodilation

loss

With hot ambient temperatures, what does decreased sympathetic activity to skin and blood vessels cause? This aids in heat (choose one: loss/decreased production)

sweating/evaporation

loss

With hot ambient temperatures, what does increased sympathetic activity to sweat glands cause? This aids in heat (choose one: loss/decreased production)

decreased metabolic activity

decreased production

With hot ambient temperatures, what does decreased sympathetic activity to brown adipose tissue cause? This aids in heat (choose one: loss/decreased production)

skeletal muscle

With hot ambient temperature the somatomotor response includes DECREASED activity of ________ ________ motor neurons

decreased metabolic activity

decreased production

With hot ambient temperatures, what does decreased somatomotor activity to skeletal muscle motor neurons cause? This aids in heat (choose one: loss/decreased production)

true

T/F voluntary behavior to change posture or seek a different location serves as a homeostatic function in homeotherms

posture

colder

Homeotherms may adopt conservation of heat _________ in the cold or seek a _________ location in the heat as a homeostatic function

Excessive exercise

excessive thyroid hormone

some medications

lesions in hypothalamus

what are possible causes of hyperthermia and heat stroke?

Heat stress -> heat cramp -> heat exhaustion -> heat stroke

what is the progression of heat stress to heat stroke?

time (In heat)

what is the factor that determines progression of heat stress to heat stroke?

organ

encephalopathy

Heat stroke lead to multi-______ dysfunction including ______________

Slowly

when treating heat stress, you want to cool the animal (choose one: slowly/quickly)

Fever

evolutionary adaptation to fight infection

pyrogen

production

conservation

Fevers result from hypothalamus exposure to _________ resulting in heat __________ and ___________ to elevate body temperature because the immune system is more effective with high heat

True

T/F fever therapy does not seem to affect the risk of death and serious adverse events

Circumventricular ograns (CVOs)

hypothalamus

where can osmoreceptors be located?

SFO (subfornical organ)

OVLT (organum vasculosum lamina terminalis)

MnPO (median preoptic nucleus)

what are the osmoreceptors of the circumventricular organs (CVO's)?

Supraoptic nucleus

paraventricular nucleus

what are the osmoreceptors of the hypothalamus?

true

T/F the circumventricular organs are around the ventricles in the brain and have NO blood brain barrier

osmoreceptors

vasopressin

sympathetic

integrative

In dehydration, increased blood osmolarity sitmulates the _____________ of the CVO's and hypothalamus. This causes increased __________ release, increased ___________ nerve activity and goes to higher ___________ centers

reabsorption

water

Vasopressin release increases ___________ of ____ in the kidneys

arterial pressure

Increased sympathetic nerve activity stimulated by osmoreceptors during dehydration leads to an increase in ________ __________

drinking

Stimulation of higher integrative center by osmoreceptors during dehydration leads to __________

decreased

renin

angiotensin II

Peripheral effects of dehydration include: dehydration causes (choose one: increased/decreased) cardiac output and arterial pressure which causes increased ______ release which stimulates increased ___________ __ release which stimulates osmoreceptors

Increased blood osmolarity

angiotensin II

what two things can stimulate osmoreceptors in the CVO's and hypothalamus?

drinking

reabsorption

water

_________ and __________ of _____ in the kidneys leads to restoration of fluid balance in response to dehydration

true

T/F drinking BEHAVIOR serves as a homeostatic funtion

conscious

does

Searching for water, remembering locations of water, and coordinating water ingestion is a (choose one: conscious/unconscious) behavior that (choose one: does/does not) require the cerebral cortex

Licking lips

lapping

swallowing

what are subconscious drinking behaviors that do not require the cerebral cortex?

No

Do subconscious drinking behaviors actually fix dehydration?

Hypothalamus

periaqueductal gray matter

other brainstem and spinal cord structures

what three regions of the brain mediate subconscious drinking behaviors?

Eating or not eating

what helps regulate energy homeostasis?

rewarding

satiety

In food deprivation, the CNS increases _________ properties of food while reducing meal induced ________ leading to increased food intake

rewarding

satiety

When overfed, the CNS inhibits _________ properties of food while enhancing meal-induced ___________ leading to reduced food intake

lateral hypothalamus (hunger center)

hunger

eating

Decreased blood sugar activates the _______ __________ which stimulates _____ which leads to _______ behaviors

AGRP/NPY neurons

ghrelin

noradrenaline

dopamine

What contributes to stimulate appetite?

Ventromedial hypothalamus (satiety center)

satiated

stop eating

increased blood sugar activates the ___________ ___________ which leads to __________ which makes you ____ _________

POMC/CART neurons

leptin

serotonin

CCK

What contribute to suppress appetite?

no appetite

What will happen if you have a lesion to the neurons that tell you to eat? (AGRP/NPY neurons)

Eat too much

What will happen if you have a lesion to the neurons that tell you to stop eating? (POMC/CART neurons)

Hypothalamus-pituitary gland axis

what provides neuroendocrine control of homeostasis?

regulatory hormones

trophic

peripheral endocrine

hormones

The hypothalamus secretes ________ __________ that stimulate that anterior pituitary gland which then secretes _________ hormones and stimulates a __________ ________ gland/organ which secretes __________ that can provide negative feedback on the anterior pituitary gland and hypothalamus

Anterior pituitary secretions

peripheral endocrine hormones

what can provide negative feedback on the hypothalamus?

peripheral endocrine hormones

what can provide negative feedback on the Anterior pituitary gland?

oxytocin

ADH

OT

ADH

The hypothalamus can secrete _______ or ___ to stimulate the posterior pituitary gland which release __ and ___ hormones which stimulate peripheral organs. Secretions from peripheral organs can provide positive or negative feedback on the hypothalamus

Negative feedback primarily

the hypothalamus- ANTERIOR pituitary gland axis can have (choose one: positive feedback primarily/negative feedback primarily/positive and negative feedback)

Positive and negative feedback

the hypothalamus- POSTERIOR pituitary gland axis can have (choose one: positive feedback only/negative feedback only/positive and negative feedback)

Baroreflex

negative feedback control of pressure by pressure

buffer

postural

gravity

flow

loss

The baroreflex is important to ______ sudden changes in pressure due to _________ changes, ________, rapid changes in blood ____ to a specific organ or immediate blood ____

Carotid sinus- CN IX

aortic sinus- CN X

what are the receptors/afferents of the baroreflex? Where are they located?

decrease

NTS

With the baroreceptor reflex, a decrease in arterial pressure leads to a(n) (choose one: increase/decrease) in baroreceptor firing rate. This is relayed to the ___

vasomotor

cardiac

vagal cardiac

In response to decreased firing of the baroreceptors, the NTS increases sympathetic __________ activity, increases sympathetic _________ activity and decreases _______ ________ activity

vascular resistance

arterial pressure

increased sympathetic vasomotor activity stimulated by the NTS due to decreased baroreceptor firing rate leads to increased ________ _________ and therefore increased ________ __________

contractility

cardiac output

arterial pressure

increased sympathetic cardiac activity stimulated by the NTS due to decreased baroreceptor firing rate leads to increased cardiac ________ which ultimately leads to increased _______ ______ to increase ________ ________

heart rate

Output

arterial pressure

Decreased vagal cardiac activity stimulated by the NTS due to decreased baroreceptor firing rate leads to increased _____ _______ to increase cardiac ________ and therefore increase _________ __________

increase

decrease

Increase in blood pressure leads to (choose one: increase/decrease) in parasympathetic tone to the heart and (choose one: increase/decrease) in sympathetic drive the the heart and vessels in order to bring the system back to homeostasis

decrease

increase

Decrease in blood pressure leads to (choose one: increase/decrease) in parasympathetic tone to the heart and (choose one: increase/decrease) in sympathetic drive the the heart and vessels in order to bring the system back to homeostasis