Chapter 33
Calcium levels in the blood are highly regulated through homeostasis. When blood calcium levels are high, the thyroid gland secretes a hormone called calcitonin, which causes increased calcium deposits in bone, decreased calcium absorption by the intestines, and decreased calcium absorption by the kidneys. When blood calcium levels drop, the parathyroid gland responds by releasing parathyroid hormone (PTH), which causes calcium to be released from bone, as well as increases calcium absorption by the intestines and kidneys. Some individuals have higher circulating calcium concentrations than is expected in healthy patients. Which answer option could explain higher circulating calcium concentrations?
Lack of functioning PTH receptors on the cells of the kidney
Lack of functioning PTH receptors on the bones
Lack of functioning calcitonin receptors on the bones
Lack of functioning PTH receptors on the cells of the intestine
Body temperature is maintained within a specific range because many physiologic and cellular functions occur optimally only within a specific range. If someone goes outside on a hot day, they begin to get hot and their body temperature can rise. The body can respond by producing sweat from sweat glands to try to cool the body down. In this example, the response to increased body temperature is initiated by the:
Hypothalamus
Circulating blood sugar levels are tightly maintained in the body. After a meal, blood sugar levels rise, and specialized cells in the pancreas release insulin to lower circulating levels of blood sugar. Some diabetics are unable to produce insulin. Which statement reflects how this would disrupt the feedback loop to decrease blood sugar levels?
Pancreatic cells do not produce insulin; therefore, the effector is broken.
The lysosome is an organelle that is important to cellular homeostasis through its degradation of different compounds. Degradative enzymes responsible for reactions within the lysosome are most efficient at pH levels below what is found in the cell. What is responsible for allowing a different pH between an organelle and the rest of the cell?
The presence of proton pumps in the lysosome membrane that allows the organelle to maintain higher concentrations of protons
The ability to maintain certain physical conditions (blood pH, body temperature, and so forth) within a narrow range of values most often depends on:
Negative feedback
A very healthy person should always have a constant heart rate and blood pressure.
False
A person who exercises for an extended amount of time will experience a lower blood pH due to increased carbon dioxide levels in the blood. This is an example of homeostasis.
False
During childbirth, the release of a hormone, oxytocin, causes an increase of uterine contractions. The increase in uterine contractions causes increases in the amount of oxytocin produced and increases the strength of contractions. This is an example of negative feedback.
False
When people have a bacterial infection, pyrogens are often released to maintain elevated body temperature, which helps kill the bacteria causing the infection. Which answer option is the most likely action of pyrogens on thermoregulation?
Pyrogens reset the set point of the sensor
If you were to sample someone’s blood throughout the day, you might find that a sample taken one hour after breakfast shows high levels of circulating proteins, whereas a sample taken just before lunch shows much lower levels of proteins. This suggests that blood protein concentrations are regulated through a negative feedback system.
False
Calcium levels in the blood are highly regulated through homeostasis. When blood calcium levels are high, the thyroid gland secretes a hormone called calcitonin, which causes increased calcium deposits in bone, decreased calcium absorption by the intestines, and decreased calcium absorption by the kidneys. In this example, the _____ is the sensor.
Thyroid gland
Chapter 35
An individual carries a mutation in one of the genes encoding olfactory sensory receptors; however, their gustatory sensory receptors appear normal. What would you predict regarding this individual’s sense of taste and smell (Hint: “taste” of food results from the combination of signals received from the brain when food is in the mouth and odors stimulate the olfactory system)?
Given how these signals are processed, the woman would have a poor sense of smell and a limited sense of taste.
If you were to look at a sensory neuron under the microscope, where would you expect to find the axon hillock?
Just next to the cell body on the side closest to the axon terminals
Semicircular canals are associated with the:
Vestibular system
Sensory receptors respond to a novel stimulus with a(n):
Initially high firing rate
Stereocilia are important for the function of:
Statocysts, hair cells in fish, vestibular systems
Crested grebes, a water bird species, perform elaborate and synchronized courtship displays during the mating season. As a researcher studying this behavior, you notice one male bird that is unable to perform the courtship display. Which region of the brain would you expect to be affected?
Parietal lobe
What type of sensory receptor is responsible for olfaction?
Chemoreceptor
Imagine that a student studies all night for an exam the next day. The student remembers (almost) everything for their test, but within a week, they forget most of what they studied. Why?
The student has not repeatedly studied the material they were tested on.
The student’s short-term memories regarding the test material were not successfully transformed into long-term memories.
New neural circuits were not formed (or strengthened) in the student’s brain.
What determines the specific wavelength of light absorbed by a cone cell?
The type of opsin present in the membrane
Mechanoreceptors respond to:
Changes in pressure.
Where on a neuron would you expect to find myelin?
Around and along the axon
