Internal Regulation

Homeostasis

• Temperature regulation and other biological processes that keep body variables within a fixed range.

ex. process resembles the thermostat in a house with heating and cooling systems.

ex. stand balance on one foot

Set Point

• single value that the body works to maintain.

ex. if blood calcium falls below 0.16 g/L, the body releases calcium from bones.

Negative Feedback

• Known as the processes that reduce discrepancies from the set point.

Allostasis

• The adaptive way, body anticipates needs depending on their situation, avoiding errors rather than just correcting them.

“variable” and “standing” in greek.

Homeostasis and Allostasis dont work perfectly bc if they do. then we wouldnt have problem such as obesity, high-blood pressure / diabetes

Ectothermic

• depends on external sources for body heat instead of generating it themselves

“cold blooded”

“poikilothermic” from greek = “varied heat”

ex. Amphibians, Reptiles and most Fish

Basal Metabolism

• The energy used to maintain a constant body temperature while at rest.

Brain Mechanism (in internal reg)

• physiological changes that regulate body temperature.

• preoptic because it is near the

  • optic chiasm, where the optic nerve cross

(Preoptic Area) (Anterior Hypothalamus) (POA/AH)

• Send output to the hindbrain’s raphe nucleus

• receives input from temperature receptors in the skin, organs and hypothalamus

• receives input from immune system → reacts to an infection by sending prostaglandins and histamines to the POA/AH

Fever

• A fever represents an increased set point for body temperature.

• hypothalamus directs the body to produce.

raphe nucleus

• controls the autonomic responses and changes in blood flow to the skin

vasopressin

• comes from the term vascular pressure

• raises blood pressure by constricting blood vessels

• also known as the “antidiuretic hormone” (ADH)

• helps you w/o going to the toilet at night

• increased secretion when sleeping to preserve body water (hindi ka naman nakakainom ng tulog)

• the increased pressure helps compensate for the decreased blood volume

• decreases urination and increases thirst

antidiuretic hormone (ADH)

• enables kidneys to reabsorb water from urine → urine is more concentrated

• diuresis = urination

Eating salty foods cause…

osmotic thirst

losing fluid by bleeding or sweating causes

hypovolemic thirst

osmotic pressure

• tendency of water to flow across a semipermeable membrane from the area of low solute concentration to the area of higher concentration

• occurs when solutes are more concentrated on one side of the membrane than the other

osmotic thirst

drive for water that helps restore the normal state

what excrete more concentrated urine to rid the body of excess sodium and maintain as much water as possible

kidney

what are the two receptors that detect osmotic pressure and the sodium content of the blood?

OVLT (organum vasculosum laminae terminalis) and the subfornical organ (SFO

OVLT (organum vasculosum laminae terminalis)

• receives input from receptors in the digestive tract, enabling it to anticipate an osmotic need before the rest of the body experiences it

where is a good position in the brain to monitor the cotents of blood where is the BBB weak? chemicals enter na hindi abot ng neurons ng ibang parts ng brain.

third ventricle

subfornical organ

• one population of neurons that increases thirst and another population that suppresses it

lateral preoptic area and surrounding parts of the hypothalamus

control drinking

supraoptic nucleus and the paraventricular nucleus (PVN)

• control the rate at which the posterior pituitary releases vasopressin.

angiotensinogen

a large protein in the blood,

renin

enzyme that splits a portion off angiotensinogen, a large protein in the blood, to form angiotensin I, which other enzymes convert to angiotensin

angiotensin II

• constricts the blood vessels, compensating for the drop in blood pressure

• helps trigger thirst, together with receptors that detect blood pressure in the large veins.

• hypovolemic thirst nadedevelop dito cus u need to restore lost salts and not just water (kaya kapag dehydrated ka, may salt ung solution na pinapainom nila sayo sa clinic, yung pangit lasa haha)

• when it reaches the brain reaches the brain, it stimulates neurons in areas adjoining the third ventricle

hypovolemic (HI-po-vo-LEE-mik) thirst,

thirst based on low volume

sodium-specific hunger

• strong preference for salty tastes

• even for extremely concentrated salt solutions that it would ordinarily reject

• depends partly on hormones (kaya s=masarap daw maaalat sa menstruating women)

When the body’s sodium reserves are low, the adrenal glands produce….

aldosterone

aldosterone

• a hormone that causes the kidneys, salivary glands, and sweat glands to retain salt

• indicates low sodium, and angiotensin

Aldosterone and angiotensin II

r change the properties of taste receptors on the tongue, neurons in the nucleus of the tractus solitarius (part of the taste system), and neurons elsewhere in the brain to increase salt intake

The small intestine has enzymes that…..

• digest proteins, fats, and carbohydrate

• s. It also absorbs digested materials into the blood, which carries those chemicals to body cells that either use them or store them for later use.

The large intestine absorbs….

water and minerals and lubricates the remaining materials to excrete them.

Lactase

• enzyme which is responsible for metabolizing lactose (sugar in milk)

• kaya hindi masyado beneficial for nutrients di tulad nung baby ka yun yung main source mo → for animals pala ito pero ganito ang analogy

• sa genes nakasasalalay if u can metabolize milk/lactose… if di keri the lactose intolerant

tryptophan

• helps the brain produce melatonin, which aids sleepiness.

• eating carbohydrates → causes _ amino acid to be high rin

• n enters the brain by an active-transport protein that it shares with phenylalanine and other large amino acids