LOs that havent been tested yet!

In a homeostatically regulated system, diagram or identify the regulated homeostatic variable, sensor, control center, effector(s), and effector response(s).

• Regulated variable: what is being kept stable (e.g., body temperature)

• Sensor (receptor): detects changes in that variable

• Control center: compares to the set point and decides what to do (often brain)

• Effectors: organs/tissues that carry out the response (muscles, glands)

• Response: the action that brings the variable back to normal (negative feedback)

Compare and contrast how the endocrine and neural systems do long-distance communication within the mammalian body.

• Nervous system: fast, uses electrical signals + neurotransmitters, short-lasting, very targeted

• Endocrine system: slower, uses hormones in bloodstream, longer-lasting, more widespread

Predict what would happen to the amount of signaling between neurons and their targets if neurotransmitter release, receptors, or clearance from the synapse were changed.

• More neurotransmitter release → stronger signaling

• More receptors → stronger response

• Faster clearance (removal) → weaker signaling

• Less release or fewer receptors → weaker signaling

anything that increases neurotransmitter presence or detection increases signaling

Predict how manipulating various parts of a growing plant shoot will influence auxin signaling and plant growth towards light.

If you remove or block parts (like the tip), auxin distribution changes → growth direction changes

Describe two ways in which the properties of auxin in plants has parallels to the properties of hormones in animals.

• Both are chemical signals that travel to target cells

• Both require specific receptors to produce a response

Explain the two ways in which the hypothalamus and pituitary gland act together to release hormones.

Anterior pituitary

• Hypothalamus releases signaling hormones → travel through blood → control anterior pituitary → releases other hormones

Posterior pituitary

• Hypothalamus makes hormones → stored and released directly by posterior pituitary

Distinguish between asexual and sexual reproduction.

• Asexual reproduction:

  • One parent

  • No gametes

  • Offspring are genetically identical (clones)

• Sexual reproduction:

  • Two parents (or two gametes)

  • Involves meiosis + fertilization

  • Offspring are genetically diverse

Use the concept of pressure to describe the movement of water and nutrients in plant xylem and phloem and blood in vertebrates.

• Blood: heart creates pressure to push blood through vessels

• Xylem (plants): water pulled up by transpiration (negative pressure)

• Phloem (plants): sugars move via pressure gradients

Trace the flow of a drop of blood through the four chambers of the heart, the great vessels, lungs, and the blood vessels (arteries, veins, and capillaries) in the systemic circulation in healthy people and people with various malformations of the heart or great vessels.

right atrium → right ventricle → pulmonary valve → pulmonary artery → lungs → left atrium → left ventricle → aortic valve opens → oxygen rich blood is pumped into aorta and rest of body

Distinguish between systolic and diastolic blood pressure.

• Systolic: pressure when the heart contracts (higher number)

• Diastolic: pressure when the heart relaxes (lower number)

predict how changes in body posture or baroreceptors would affect homeostatic control of blood pressure.

• Baroreceptors detect pressure changes (in arteries)

• Standing up quickly → blood pools in legs → BP drops

• Baroreceptors trigger:

  • ↑ heart rate

  • vasoconstriction
    👉 This restores blood pressure (negative feedback)

Predict how blood pH levels will change as a result of the kidney’s reabsorption or excretion of bicarbonate ions, and vice versa.

• If kidneys reabsorb more bicarbonate → pH increases (more basic)

• If kidneys excrete bicarbonate → pH decreases (more acidic)

Describe how glomerular filtration rate is controlled through the myogenic mechanism and activation of the renin-angiotensin-aldosterone system.

Myogenic mechanism

• Afferent arteriole constricts if BP is too high

• Keeps GFR stable automatically

Renin-Angiotensin-Aldosterone System (RAAS)

• Activated when BP is low

• Increases blood pressure by:

  • vasoconstriction

  • retaining water and sodium

Hypothesize how a channel or another molecule in a plant or animal would detect outside stimuli such as touch, chemicals, or light.

through open channels

Predict how changes in light levels, retinal, opsins, and cation channels in photoreceptors affect the photoreceptor’s membrane potential and neurotransmitter release.

In the dark:

• cation channels open → cell is depolarized

• continuous neurotransmitter release

in the light:

• light activates retinal + opsins

• cation channels close → hyperpolarization

• less neurotransmitter released