Practical Exam 1 Questions (BIO lab)

What is a sagittal section of tissue?

A cut that divides the tissue into right and left sides.

What is a parasagittal section of tissue?

A cut that divides the tissue into unequal right and left sides.

What is a coronal (frontal) section of tissue?

A cut that divides the tissue into front (anterior) and back (posterior) parts.

What is a transverse (cross) section of tissue?

A cut that divides the tissue into top (superior) and bottom (inferior) parts.

How do steroid-based hormones activate genes in a target cell?

They enter the cell and bind to receptors that act directly on the DNA to start transcription.

How do amino acid-based hormones activate genes in a target cell?

They bind to receptors on the outside of the cell membrane and use a second-messenger system.

What is the fundamental difference between how steroid and amino acid-based hormones interact with their target cells?

Steroid hormones go inside the cell, while amino acid-based hormones stay on the outside.

Why can steroid hormones pass directly through the plasma membrane while amino acid-based hormones cannot?

Steroid hormones are lipid-soluble (made of fat), allowing them to pass through the fatty cell membrane.

What is the chemical structure of T3 (triiodothyronine)?

It is made of two tyrosine molecules with three bound iodine atoms.

What is the chemical structure of $T_4$ (thyroxine)?

It is made of two tyrosine molecules with four bound iodine atoms.

What specific molecule is joined with iodine atoms to form T3 and T4 hormones?

Tyrosine.

How many iodine atoms are attached to the tyrosine molecule in $T_3$?

Three.

How many iodine atoms are attached to the tyrosine molecule in T4?

Four.

What hormone stimulates calcium deposition in bones?

Calcitonin.

What hormone is the antagonist to calcitonin?

Parathyroid hormone (PTH).

What is the overall effect of calcitonin on blood calcium levels?

It lowers the levels of calcium in the blood.

What is the overall effect of parathyroid hormone (PTH) on blood calcium levels?

It raises the levels of calcium in the blood.

In thyroid histology, what are the follicular cells?

They are epithelial cells that form the walls of the follicles and produce thyroid hormone.

In thyroid histology, what are the parafollicular cells (C cells)?

They are cells located between the follicles that produce the hormone calcitonin.

In thyroid histology, what are the follicles and the colloid?

Follicles are hollow spheres, and colloid is the amber-colored fluid inside them that stores hormone precursors.

What hormone do follicular cells of the thyroid produce?

Thyroid hormone ($T_3$ and $T_4$).

What hormone do parafollicular cells (C cells) of the thyroid produce?

Calcitonin.

What is the anterior lobe of the pituitary gland also called?

Adenohypophysis.

What is the posterior lobe of the pituitary gland also called?

Neurohypophysis.

What is the infundibulum of the pituitary gland?

The stalk that connects the pituitary gland to the hypothalamus.

What are the three parts of the anterior pituitary (adenohypophysis)?

Pars distalis, pars intermedia, and pars tuberalis.

What hormones are released by the anterior lobe of the pituitary gland?

GH, TSH, ACTH, FSH, LH, and PRL.

What hormones are released by the posterior lobe of the pituitary gland?

Oxytocin (OT) and antidiuretic hormone (ADH).

Which hormones released by the pituitary gland are amino acid-based?

All of them.

Which hormones released by the pituitary gland are steroid-based?

None of them.

What is the function of growth hormone (GH)?

It stimulates most body cells to enlarge and divide, especially bone and skeletal muscle.

What is the function of thyroid-stimulating hormone (TSH)?

It stimulates the thyroid gland to release thyroid hormones.

What is the function of adrenocorticotropic hormone (ACTH)?

It stimulates the adrenal cortex to release corticosteroid hormones.

What is the function of follicle-stimulating hormone (FSH)?

It stimulates the production of gametes (eggs or sperm).

What is the function of luteinizing hormone (LH)?

It triggers ovulation and the production of estrogen, progesterone, or testosterone.

What is the function of prolactin (PRL)?

It stimulates milk production in the breasts.

What is the function of melanocyte-stimulating hormone (MSH)?

It stimulates melanocytes in the skin to increase pigmentation.

What is the function of oxytocin (OT)?

It stimulates uterine contractions during childbirth and triggers milk ejection.

What is the function of antidiuretic hormone (ADH)?

It tells the kidneys to reabsorb water to prevent urine formation.

What are the three cell populations found in the pancreatic islets?

Alpha cells, beta cells, and delta cells.

What hormone do alpha cells of the pancreas produce, and what is its function?

They produce glucagon, which raises blood sugar levels.

What hormone do beta cells of the pancreas produce, and what is its function?

They produce insulin, which lowers blood sugar levels.

What hormone do delta cells of the pancreas produce, and what is its function?

They produce somatostatin, which inhibits the release of insulin and glucagon.

How are alpha cells identified in a pancreatic histology image?

They are the glucagon-producing cells within the pancreatic islets.

How are beta cells identified in a pancreatic histology image?

They are the insulin-producing cells within the pancreatic islets.

How are delta cells identified in a pancreatic histology image?

They are a small population of cells in the pancreatic islets that produce somatostatin.

What are pancreatic acini?

They are exocrine cells that produce digestive enzymes.

What are pancreatic islets (islets of Langerhans)?

They are small clusters of endocrine cells scattered throughout the pancreas.

Does the pancreas function only as an endocrine gland?

No, it also functions as an exocrine gland.

What are the endocrine functions of the pancreas?

Producing hormones like insulin and glucagon to regulate blood sugar.

What are the exocrine functions of the pancreas?

Producing digestive enzymes that are carried by ducts to the small intestine.

What hormones are released by the thyroid gland and what are their functions?

Thyroid hormone (metabolism) and calcitonin (blood calcium regulation).

What hormones are released by the pancreas and what are their functions?

Insulin (lowers blood sugar) and glucagon (raises blood sugar).

What hormones are released by the adrenal gland and what are their functions?

Corticosteroids (stress and mineral balance) and catecholamines (fight or flight).

What hormone is released by the pineal gland and what is its function?

Melatonin, which regulates sleep-wake cycles.

What hormones are released by the testes and what are their functions?

Testosterone, which handles male reproductive maturation and sperm production.

What hormones are released by the ovaries and what are their functions?

Estrogen and progesterone, which handle female reproductive maturation and uterine changes.

What is the zona glomerulosa of the adrenal cortex?

The outermost layer of the cortex.

What is the zona fasciculata of the adrenal cortex?

The thick middle layer of the cortex.

What is the zona reticularis of the adrenal cortex?

The innermost layer of the cortex.

What is the adrenal medulla?

The inner core of the adrenal gland made of nervous tissue.

What class of hormones is released by the zona glomerulosa, and what is their function?

Mineralocorticoids, which regulate electrolyte and water balance.

What class of hormones is released by the zona fasciculata, and what is their function?

Glucocorticoids, which help the body resist stressors and regulate metabolism.

What class of hormones is released by the zona reticularis, and what is their function?

Gonadocorticoids (sex hormones), mainly weak androgens.

What hormones are released by the adrenal medulla, and what is their function?

Epinephrine and norepinephrine, which stimulate the fight-or-flight response.

Describe the hormone pathway using the hypothalamic-hypophyseal tract.

Hormones are made in the hypothalamus, travel down axons, and are stored in the posterior pituitary until release.

What is the hypothalamic-hypophyseal tract?

A bundle of nerve fibers that connects the hypothalamus to the posterior pituitary.

Which cells of the hypothalamus produce oxytocin?

Neurons in the paraventricular nucleus.

Which cells of the hypothalamus produce antidiuretic hormone (ADH)?

Neurons in the supraoptic nucleus.

How do hormones travel from the hypothalamus to the posterior pituitary?

They travel down the axons of the hypothalamic-hypophyseal tract.

How do hormones travel from the hypothalamus to the anterior pituitary?

They travel through a special network of blood vessels called the hypophyseal portal system.

What are tropic hormones?

Hormones that regulate the secretory action of other endocrine glands.

What are examples of tropic hormones?

TSH, ACTH, FSH, and LH.

What is the difference between a tropic hormone and a non-tropic hormone?

Tropic hormones target other endocrine glands, while non-tropic hormones target non-endocrine body cells directly.