Chapter 9 quiz

which event will trigger osmotic thirst?

A salty meal

Long-term energy storage is accomplished by storage of fat in _______ tissue.

Adipose

Which hormone causes blood vessels to constrict?

Angiotensin II

HIG Using examples, define and describe negative feedback as it applies to homeostasis.

The process whereby a system monitors its own output and reduces its activity when a set point is reached. Example: Household thermostat. The system turns off when it reaches a set zone.

Which statement correctly describes osmotic pressure?

The tendency of a solvent to move across a membrane in order to equalize the concentration of solute on both sides of the membrane

HIG Although the concept of homeostasis primarily relates to the physical internal environment, behavior can play an important role too. How?

In general, both ectotherms and endotherms deploy three kinds of temperature-regulating behavior: (1) behaviors that change exposure of the body surface—for example, by huddling or extending limbs; (2) behaviors that change external insulation, such as by using clothing or nests; and (3) behaviors that change surroundings, by moving into the sun, into the shade, or into a burrow.

Behavioral regulation of body temperature, like moving closer to the fire, is especially affected by lesions of the

Lateral hypothalamus

HIG Distinguish between endotherms and ectotherms, and give a few examples of each.

Mammals are endotherms - we make our own heat inside our bodies. Ectotherms - rely on heat sources outside the body. Snakes and lizards.

HIG Define homeostasis, and discuss its relation to the psychological concept of motivation. Why do homeostatic systems tend to have a set zone instead of a set point?

a relatively stable, balanced internal environment that is optimized for cellular activities. Deviations from this state can affect motivation. Super thirsty, seek water. Cold, seek heat. Have a set zone to allow for a little bit of tolerance, like a furnace system in a house. This keeps the system from going on and off too frequently, and is less rigid.

It is thought that each individual's _______ is in two-way communication with the brain via chemical signals and the _______.

enterotype; vagus nerve

Amino acids that are not manufactured by our bodies are classified as

essential

HIG Many homeostatic systems feature redundancy. What is it and why is it important?

our bodies tend to have multiple mechanisms for monitoring our stores, conserving remaining supplies, obtaining new resources, and shedding excesses. Loss of function in one part of the system usually can be compensated for by the remaining parts.

Thermoregulation is considered a negative feedback system because

restoring the desired temperature turns off the response.

The brain responds to hypovolemia by triggering both thirst and hunger for

salt

_______ involves periodic binge eating followed by _______ or taking laxatives to avoid weight gain.

binging; vomiting

Two physiological responses to hypovolemia are _______ of blood vessels and the secretion of _______ by the posterior pituitary.

constriction; vasopressin

Which hormone monitors the body's longer-term energy reserves in the form of fat?

leptin

The population of beneficial bacteria, fungi, and viruses that inhabit the large intestine of human beings is referred to as a

microbiome

HIG What is the normal concentration of salt in extracellular fluid? What happens to cells if the saltiness of the extracellular fluid increases or decreases?

0.9%. Because water moves to produce uniform saltiness (see Figure 9.5), cells will lose water if placed in a saltier solution and will gain water in a less salty solution. If excessive, this movement of water will damage or kill the cell.

Which example demonstrates ectothermic behavior?

A turtle basking on a sunny log

Which method is not a current strategy for treating obesity?

Drugs that increase digestive acid levels in the stomach

Lesions to which brain region would impair physiological responses to temperature in endotherms?

Preoptic area

HIG Briefly describe diffusion and osmosis, and define osmotic pressure. How do these relate to the composition of fluids in the intracellular versus extracellular compartments?

Diffusion - The spontaneous spread of solute molecules from an area of high concentration to an area of low concentration through a solvent until a uniform solute concentration is achieved. Osmosis - is the movement of water molecules that occurs so as to equalize the concentration of two solutions that are separated by a semipermeable membrane Osmotic pressure - The tendency of a solvent to move across a membrane in order to equalize the concentration of solute on both sides of the membrane. We feel thirsty due to loss of water. In this case, not only is the volume of the extracellular fluid decreased, but also the solute concentration of the extracellular fluid is increased. As a result of the increase in extracellular saltiness, water is pulled out of cells through osmosis and we experience osmotic thirst

HIG Distinguish between hypovolemic and osmotic thirst, and identify the physiological sensors that detect each condition.

Hypovelemic - A desire to ingest fluids that is stimulated by a reduction in volume of the extracellular fluid. Osmotic - A desire to ingest fluids that is stimulated by high concentration of solute (like salt) in the extracellular compartment.

HIG Provide a review of how glucose is used, stored, and retrieved from storage. Be sure to identify the roles of pancreatic hormones in each step.

Glucose - a simple sugar obtained through breakdown of other molecules. Need steady supply between meals. Short term storage - converted to glycogen.

The body stores glucose for later use after first converting it to a more complex form called

Glycogen

High circulating levels of leptin activate the _______ satiety neurons and simultaneously inhibit the _______ hunger neurons.

POMC; NPY

Which statement about anorexia nervosa is true?

People with anorexia think about food a great deal.

HIG What is basal metabolism?

The use of energy for processes such as heat production, maintenance of membrane potentials, and all the other basic life-sustaining functions of the body. Majority of food energy is spent here, 80-90%

HIG Define allostasis. How does allostasis relate to homeostasis?

The varying behavioral and physiological adjustments that an individual makes in order to maintain optimal (rather than unchanging) functioning of a regulated system in the face of changing environmental stressors.

What is the significance of a set zone, as opposed to a precise set point, in terms of thermoregulation?

The wide variety of conditions that animals face makes a tolerance, or set zone, instead of a precise set point, more adaptable.

HIG After so many millions of years of evolution, why do we still have body fluids with composition resembling dilute seawater?

When multicellular organisms evolved much later and began to exploit opportunities on land and in the air, they had no choice but to bring along with them the watery environment that their cells needed to survive. For this reason, most organisms evolved homeostatic systems that ensure that the composition of their body fluids closely resembles dilute seawater