Anatomy and Physiology II (M8) Comprehensive Lecture Exam

Correct Answer:

In the external ear canals

Explanation:

Cerumen, commonly known as earwax, is produced by ceruminous glands located in the external auditory canal. Its purpose is to protect the ear by trapping dust, microorganisms, and other foreign particles. When produced in excess, cerumen can build up in the external ear canal, potentially causing discomfort, hearing loss, or infections.

Why Other Options are Wrong:

In the nose

The nose contains mucous membranes, not ceruminous glands. Mucus, not cerumen, is produced there.

On the teeth

The teeth may accumulate plaque or tartar, but not cerumen. Cerumen is limited to the ear canal.

On the eyelids and eyes

The glands around the eyes produce tears and oils (like meibum), not cerumen. Earwax is not secreted or found in this region.

Correct Answer: D. Collapse

Explanation of the Correct Answer:

D. Collapse

Under normal conditions, the intrapleural pressure (the pressure within the pleural cavity between the lungs and the chest wall) is slightly lower than atmospheric pressure. This negative pressure is crucial because it helps keep the lungs expanded by creating a suction effect that holds the lungs against the inner chest wall.

If the intrapleural pressure rises to equal or exceed atmospheric pressure, this suction is lost, and the lungs will recoil and collapse. This condition is known as pneumothorax. It can occur due to trauma (such as a punctured chest wall or ruptured alveoli), allowing air to enter the pleural space and disrupting the pressure balance.

Why the Other Options Are Incorrect:

A. Inhalation

Inhalation occurs when intrapleural pressure drops further below atmospheric pressure, allowing the lungs to expand and air to flow in. If intrapleural pressure increases to match or exceed atmospheric pressure, inhalation becomes impossible, not more effective.

B. Overinflation

Overinflation of the lungs happens when there's excessive air trapped inside, such as in conditions like emphysema. However, if intrapleural pressure equals or exceeds atmospheric pressure, it would oppose lung inflation, not promote it. Overinflation is not the outcome in this case.

C. Burst

Lungs do not burst from increased intrapleural pressure. Instead, they recoil inward and collapse due to the loss of the negative pressure keeping them expanded. Bursting would require excessive internal pressure, not an increase in surrounding pressure.

Correct Answer: B. Placenta and attached fetal extraembryonic membranes

Explanation of the Correct Answer:

B. Placenta and attached fetal extraembryonic membranes

The term "afterbirth" refers to the placenta and the fetal extraembryonic membranes (such as the amnion and chorion) that are expelled from the mother’s body after the birth of the baby. After the baby is born, the placenta detaches from the uterine wall and is expelled during the third stage of labor. The placenta is a vital organ that provided oxygen and nutrients to the fetus throughout pregnancy, and the expulsion of the placenta is a normal part of the birth process.

Why the Other Options Are Incorrect:

A. Amniotic fluids

Amniotic fluids are the liquid that surrounds and protects the fetus in the amniotic sac. While the amniotic fluid is expelled after birth (if the membranes rupture during labor), it is not referred to as the "afterbirth."

C. Urine

Urine is waste produced by the kidneys. It is not part of the afterbirth process. The production and elimination of urine occur continuously throughout pregnancy, not specifically as the afterbirth.

D. Meconium, bile, and other wastes

Meconium is the first stool passed by a newborn, and bile is a digestive secretion produced by the liver. While meconium is passed by the newborn after birth, it is not considered part of the afterbirth. Bile and other wastes are not involved in the expulsion of the placenta and extraembryonic membranes.

Correct Answer:

A. Lung

Explanation:

Terminal bronchioles are the final branches of the conducting airway system before air reaches the respiratory zone (alveoli). They are found within the lungs, where they deliver air to the alveolar ducts and sacs for gas exchange.

Why Other Options are Wrong:

Heart

The heart is part of the cardiovascular system, not the respiratory tract. It has no bronchioles.

Femur

This is a long bone in the thigh, part of the skeletal system, and not related to respiratory anatomy.

Diaphysis

This refers to the shaft of a long bone. It’s also part of the skeletal system and unrelated to the lungs or bronchioles.

Correct Answer: B. Antidiuretic hormone (ADH) and oxytocin

Explanation of the Correct Answer:

B. Antidiuretic hormone (ADH) and oxytocin

The posterior pituitary (also called the neurohypophysis) stores and releases two hormones: ADH (antidiuretic hormone) and oxytocin. However, these hormones are not synthesized in the posterior pituitary. They are produced in the hypothalamus (specifically, in the supraoptic and paraventricular nuclei), then transported down nerve axons and stored in the posterior pituitary until released into the bloodstream.

ADH helps regulate water balance by promoting water reabsorption in the kidneys, and oxytocin stimulates uterine contractions during labor and milk ejection during breastfeeding.

Why the Other Options Are Incorrect:

A. No hormones are made by the posterior pituitary

This statement is technically true, but it is misleading in this context. While it is correct that the posterior pituitary does not synthesize hormones, it does release hormones (ADH and oxytocin) made by the hypothalamus. Since the question asks what hormones are "released" (not "made"), this choice is incorrect.

C. Stimulating hormones

This refers to hormones such as TSH (thyroid-stimulating hormone), FSH (follicle-stimulating hormone), and LH (luteinizing hormone), which are released by the anterior pituitary, not the posterior pituitary.

D. Releasing and inhibiting hormones

These are secreted by the hypothalamus and act on the anterior pituitary, not the posterior pituitary. They regulate the release of anterior pituitary hormones but are not released by the posterior pituitary.

Correct Answer:

Small intestine

Explanation:

The small intestine is the main site for nutrient absorption. Specifically, the jejunum and ileum absorb carbohydrates, proteins, fats, vitamins, and minerals into the bloodstream through structures called villi and microvilli.

Why Other Options are Wrong:

Lungs

These are part of the respiratory system and are involved in gas exchange (oxygen and carbon dioxide), not nutrient absorption.

Kidney

The kidneys filter blood and maintain fluid/electrolyte balance. They excrete waste, not absorb nutrients.

Large intestine

This mainly absorbs water and electrolytes. Very few nutrients are absorbed here.

Correct Answer:

Cardiac output

Explanation:

The sympathetic nervous system, part of the autonomic nervous system, is responsible for the "fight or flight" response. When it is activated, it increases cardiac output by raising heart rate and the strength of heart contractions. This helps prepare the body to respond to stressful situations by delivering more oxygen and nutrients to vital organs and muscles.

Why Other Options are Wrong:

Gastrointestinal activity

The sympathetic nervous system inhibits gastrointestinal activity. Digestive processes are slowed down to conserve energy and redirect blood flow to muscles during stress or emergency.

Pancreatic activity

Pancreatic secretion of digestive enzymes and insulin is reduced during sympathetic stimulation. The body prioritizes glucose conservation and availability for muscle activity over digestion or storage.

Uterine activity

The sympathetic nervous system generally inhibits uterine activity. Its influence is more prominent during labor under certain conditions but is not typically associated with increasing uterine contractions under normal sympathetic stimulation.

Correct Answer:

Urethra

Explanation:

In males, the urethra serves a dual purpose: it carries urine from the bladder to be excreted and also semen during ejaculation. It is part of both the urinary system and the male reproductive system, making it unique in its dual role.

Why Other Options are Wrong:

Testis

This is exclusively part of the reproductive system, responsible for producing sperm and testosterone.

Epididymis

Also part of the reproductive system only. It stores and matures sperm, but plays no role in urination.

Ureter

Part of the urinary system only. It transports urine from the kidneys to the bladder and is not involved in reproduction.

Correct Answer: D. External anal sphincter

Explanation of the Correct Answer:

D. External anal sphincter

The external anal sphincter is composed of skeletal muscle, which means it is under voluntary control. It is regulated by the somatic nervous system, specifically under the control of the cerebral cortex, allowing a person to consciously initiate or delay defecation. This muscle plays a crucial role in maintaining fecal continence and is the last barrier before waste is expelled from the body.

Why the Other Options Are Incorrect:

A. Pyloric sphincter

This sphincter regulates the passage of partially digested food (chyme) from the stomach into the duodenum (first part of the small intestine). It is made of smooth muscle and is under involuntary control, managed by the autonomic nervous system and hormonal signals.

B. Ileocecal valve

This valve separates the small intestine (ileum) from the large intestine (cecum). It is also made of smooth muscle and functions involuntarily, helping prevent backflow of colonic contents into the small intestine.

C. Internal anal sphincter

The internal anal sphincter is made of smooth muscle and is involuntarily controlled by the autonomic nervous system. It maintains constant tone to prevent involuntary passage of feces and relaxes reflexively when the rectum is full.