Anatomy and Physiology II (M8) Comprehensive Lecture Exam

Correct Answer: A. Adipose tissue deposition in the breasts, hips, and thighs.

Explanation of the Correct Answer:

A. Adipose tissue deposition in the breasts, hips, and thighs

Estrogens are primary female sex hormones that play a key role in the development of secondary sexual characteristics. One of their effects is the promotion of fat storage in specific areas of the body, such as the breasts, hips, and thighs. This contributes to the characteristic body shape seen in females, especially during puberty and reproductive years.

Why the Other Options Are Incorrect:

B. Deepening of the voice

Deepening of the voice is typically associated with the effects of testosterone, not estrogen. Testosterone causes the vocal cords to thicken and lengthen, which results in a deeper voice. Estrogen does not have this effect and, in fact, typically results in a higher-pitched voice.

C. Increased erythrocyte production

Erythropoiesis, or the production of red blood cells, is primarily regulated by erythropoietin, a hormone produced by the kidneys. Estrogen does not directly influence erythropoiesis in the same way that erythropoietin does. In fact, increased estrogen levels can sometimes lead to a mild suppression of red blood cell production.

D. Increased skeletal muscle mass

Skeletal muscle mass is primarily influenced by androgens like testosterone. Estrogen generally has a less pronounced effect on muscle growth. In fact, higher estrogen levels can lead to a decrease in muscle mass relative to men who have higher testosterone levels, as testosterone promotes muscle growth.

Correct Answer: A. QRS wave

Explanation of the Correct Answer:

A. QRS wave

The QRS wave (or QRS complex) represents ventricular depolarization, which is the electrical activity that triggers contraction of the ventricles. If ventricular depolarization occurs abnormally slowly, the QRS wave becomes widened or prolonged on the ECG. This is because the time it takes for the electrical impulse to spread through the ventricles is longer than normal. Conditions such as bundle branch blocks or ventricular conduction delays are known to slow depolarization and are clearly reflected as changes in the QRS complex.

Why the Other Options Are Incorrect:

B. T wave

The T wave represents ventricular repolarization, not depolarization. Abnormalities in the T wave reflect issues with the recovery of the ventricles after contraction, not with the initial spread of the electrical signal.

C. R-T interval

The R-T interval includes both ventricular depolarization and repolarization, but it is mainly used to assess the overall time the ventricles spend in the action potential phase. While it might be secondarily affected, it is not the most specific or directly affected by slow depolarization.

D. P wave

The P wave reflects atrial depolarization, not ventricular. Slow ventricular depolarization would not alter the P wave.

Correct Answer: C. 3.6.1.4.2.5

Explanation of the Correct Answer:

C. 3.6.1.4.2.5

This is the correct physiological order in which the action potential travels through the heart's conduction system.

3. sinoatrial (SA) node

This is the pacemaker of the heart. It initiates the electrical impulse that sets the rhythm of the heartbeat.

4. atrioventricular (AV) node

The impulse reaches the AV node next, where it is briefly delayed. This allows the atria to contract and push blood into the ventricles before they contract.

5. atrioventricular (AV) bundle

The impulse then travels from the AV node into the AV bundle, also called the bundle of His.

6. right and left bundle branches

From the AV bundle, the signal travels down the right and left bundle branches located in the interventricular septum.

7. Purkinje fibers

The impulse spreads through the Purkinje fibers, which rapidly conduct the signal throughout the ventricular walls.

8. contractile cells of cardiac muscle tissue

Finally, the signal reaches the contractile cells of the ventricles, causing them to contract and pump blood.

Why the Other Options Are Incorrect:

A. 3.1.6.4.5.2 places the AV bundle before the AV node and ends prematurely.

B. 3.1.6.4.2.5 has incorrect placement of AV bundle before the AV node.

D. 3.6.4.1.7.5 includes "7," which is not a valid part of the list and places steps out of order.

Correct Answer: D. Gametes

Explanation of the Correct Answer:

The testes are the gonads in males, meaning they are the reproductive organs responsible for producing gametes (specifically sperm) and sex hormones (such as testosterone).

Similarly, sperm are the gametes produced by the testes in males. Gametes are reproductive cells (sperm in males and ova in females) that combine during fertilization to form a zygote.

Why the Other Options Are Incorrect:

A. Sex hormones:

While the testes produce sex hormones (like testosterone), sperm themselves are not hormones. The relationship in the analogy is about reproductive cells (testes and sperm), not hormones.

B. Ova:

Ova are the female gametes, produced by the ovaries. The analogy is comparing male reproductive cells (sperm) to male reproductive organs (testes), not to female reproductive cells.

C. Estrogen:

Estrogen is a female sex hormone produced primarily by the ovaries. It is not related to sperm directly and does not fit the analogy.

Correct Answer: B. Trachea

Explanation of the Correct Answer:

B. Trachea

The trachea, also known as the windpipe, is part of the lower respiratory tract, not the upper respiratory tract. It begins at the larynx and extends down into the chest, where it branches into the left and right bronchi leading to the lungs. The trachea is responsible for carrying air from the upper respiratory structures into the lungs, but it is anatomically part of the lower respiratory tract.

Why the Other Options Are Correct:

A. Larynx

The larynx (voice box) is located at the junction of the pharynx and the trachea and is considered part of the upper respiratory tract. It plays a critical role in voice production, as well as protecting the trachea from food aspiration through the epiglottis.

C. Pharynx

The pharynx, also known as the throat, is part of the upper respiratory tract. It connects the nasal and oral cavities to the larynx and esophagus. It serves as a passageway for both air (to the lungs) and food (to the esophagus).

D. Nose

The nose is the entry point for air and is also part of the upper respiratory tract. It filters, warms, and humidifies the air before it enters the lungs, and it plays an important role in the sense of smell.

Correct Answer:

Lactic acid

Explanation:

During anaerobic respiration, when oxygen levels are low, cells break down glucose without oxygen. This process produces lactic acid as a byproduct. The accumulation of lactic acid in muscle tissues leads to a decrease in pH, contributing to the burning sensation and muscle fatigue experienced during intense physical activity.

Why Other Options are Wrong:

Adenosine triphosphate (ATP)

ATP is the main energy currency of the cell and is produced during cellular respiration. It does not cause a burning sensation; rather, its depletion leads to fatigue. It is not a byproduct of anaerobic respiration that builds up in muscles.

Creatine-phosphate

Creatine phosphate is a high-energy compound used to regenerate ATP during the initial seconds of muscle activity. It helps provide energy quickly but does not cause any burning sensation. It is also not produced in excess during anaerobic metabolism.

Adenosine diphosphate (ADP)

ADP is formed when ATP loses a phosphate group. Like ATP, it plays a role in energy transfer but does not accumulate in a way that causes burning. It is involved in metabolic cycling, not in producing soreness or discomfort.

Correct Answer: B. Hormones

Explanation of the Correct Answer:

Hormones are chemical messengers that are released by endocrine glands into the bloodstream. They travel throughout the body and regulate the functions of target cells or organs, often influencing growth, metabolism, mood, reproduction, and other physiological activities. Examples include insulin (from the pancreas), estrogen (from the ovaries), and thyroid hormones (from the thyroid gland).

Why the Other Options Are Incorrect:

A. Antibodies

Antibodies are proteins produced by the immune system (specifically B cells) to identify and neutralize foreign invaders like bacteria and viruses. They are not involved in chemical signaling by endocrine glands.

C. Electrolytes

Electrolytes are ions (such as sodium, potassium, calcium, and chloride) that help maintain fluid balance, nerve conduction, and muscle function. They are not chemical messengers and are not secreted by endocrine glands.

D. Neurotransmitters

Neurotransmitters are chemical messengers released by neurons (nerve cells), not endocrine glands. They transmit signals across synapses between nerve cells or from nerves to muscles.

Correct Answer:

Appearance of goose bumps.

Explanation:

Arrector pili are small, involuntary muscles attached to hair follicles. When they contract in response to cold or emotional stimuli (like fear), they pull the hair upright, creating what we know as "goose bumps." This reaction is a vestigial reflex meant to trap heat by raising body hair, which was more effective in fur-covered animals.

Why Other Options are Wrong:

Production of sweat.

Sweat production is carried out by eccrine and apocrine glands, not arrector pili muscles.

Acceleration of wrinkling in aging.

Wrinkling results from changes in collagen and elastin in the skin over time, not from muscle contractions.

Increase in skin pigmentation.

Skin pigmentation is controlled by melanocytes and influenced by hormones and UV exposure—not by arrector pili muscles.

Correct Answer: B. lower limb

Explanation of the Correct Answer:

B. lower limb

The external iliac artery is one of the major arteries that supplies blood to the lower half of the body. It branches from the common iliac artery, which is itself a branch of the abdominal aorta. The external iliac artery runs along the pelvis and, when it passes under the inguinal ligament, it becomes the femoral artery, which supplies blood to the thigh, leg, and foot. Therefore, damage to the external iliac artery would most directly affect the blood flow to the lower limbs, leading to potential ischemia (lack of oxygenated blood) and other related symptoms in the legs and feet.

Why the Other Options Are Incorrect:

A. brain

The brain receives blood primarily through the vertebral arteries (which join to form the basilar artery) and the internal carotid arteries. These arteries are not directly impacted by the external iliac artery, as they are located much higher up in the body. Therefore, damage to the external iliac artery would not affect blood flow to the brain.

C. upper limb

The upper limbs are supplied by the subclavian arteries, which branch off from the brachiocephalic artery (on the right) or the aortic arch (on the left). These arteries are also far removed from the external iliac artery and are not affected by its condition.

D. abdominal organs

The abdominal organs receive blood through several arteries including the celiac trunk, the superior mesenteric artery, and the inferior mesenteric artery. These vessels are not part of the distribution of the external iliac artery, so damage to the external iliac artery would not affect blood flow to the abdominal organs.