Module Test 2

Lungs

• The optimal condition in the lungs is low PCO2 in the alveoli and high in the capillaries.
• CO₂ moves from the blood plasma into the alveolus.
• CO₂ also joins with H₂O to make H₂CO₃.
• O₂ moves from the alveolus into the blood plasma.
• CO₂ joins with Hb (hemoglobin) to make HbCO₂ (carbaminohemoglobin).
• O₂ joins with HHb to make HbO₂ + H⁺.

Cells next to the basement membrane of the seminiferous tubules

• Spermatogonia cells lie next to the basement membrane of the seminiferous tubules
• Sertoli cells function in support and regulation of sperm development

Hormone effects of somatotropin

• Somatotropin does not decrease growth and development of bones and cartilage.
• It promotes protein synthesis and tissue building via IGFs.
• Somatotroin stimulates lipolysis so tissues use fatty acids rather than glucose.
• It stimulates the liver to break down glycogen to glucose.
• Hypothalamus releases growth hormone-releasing hormone (GHRH)
• GHRH stimulates the anterior pituitary to release growth hormone (GH)
• High IGF-1 levels perceived by the hypothalamus cause a release of growth hormone-inhibiting hormone (GHIH) to inhibit GH release.
• GH stimulates adipose cells to break down stored fat to fuel growth effects.
• GH increases the uptake of amino acids from the blood to enhance cellular proliferation and reduce apoptosis.
• GH stimulates the liver to break down glycogen into glucose, therefore fueling growth effects.
• The liver releases IGF-1, further stimulating growth effects.

Fetal vs Adult Hemoglobin

• Fetal Hb has a higher affinity for O₂than adult Hb.

Inhibin

• In males, the protein hormone inhibin is produced by Sertoli cells and inhibits the secretion of FSH.
• LH and FSH stimulate spermatogenesis and testosterone secretion by the testes.
• Testosterone and inhibin inhibit the secretion of GnRH by the hypothalamus, LH by the pituitary, and FSH by the pituitary.

RAAS component production

• The liver produces angiotensinogen as part of the RAAS (Renin-Angiotensin-Aldosterone System).
• Renin acts on angiotensinogen to form angiotensin I.
• ACE (angiotensin-converting enzyme) is released from the lungs, and acts on angiotensin I to form angiotensin II.
  • Angiotensin II acts on the adrenal gland to stimulate the release of aldosterone.
  • Aldosterone acts on the kidneys to stimulate reabsorption of salt (NaCl) and water (H₂O).
• Angiotensin II also acts directly on blood vessels, stimulating vasoconstriction.
• The Renin-angiotensin system system is triggered by a drop in blood pressure or fluid volume.

Adult Ovary

• Primordial follicles are the most common type of follicles in the adult ovary.
• The ovary contains stroma on the outside, and germinal epithelium on the surface, and the cortex.
• Ovum is produced within the follicle

Respiratory Tract

• The most sensitive region of the respiratory tract for triggering the cough reflex is the carina.

Autocrines

• Autocrines are local hormones that act on the same cell that secreted them. They are a form of chemical signaling.
• Autocrine cell targets itself.
• Signaling across gap junctions targets a cell connected by gap junctions.
• Paracrine cell targets a nearby cell.
• Endocrine cell target a distant cell through the bloodstream.

Testosterone Secretion

• LH directly stimulates testosterone secretion in males.
• FSH in males acts indirectly with testosterone to stimulate spermatogenesis

Endocrine vs Nervous Signaling Differences

• Chemical messengers travel a longer distance in the endocrine system compared to the nervous system.
• The nervous system sends messages via chemical and electrical signals down the axons of neurons and across synapses to target cells and is generally responsible for controlling rapid movement and sensations.
• The endocrine system sends messages via chemical signals (hormones), which are secreted by endocrine cells into the circulatory system and influence target cells at a distance and is responsible for slower, longer-term regulation.

Adrenal Gland

• The zona glomerulosa region of the adrenal gland releases mineralocorticoids.
• The zona fasciculata releases Glucocorticoids
• The zona reticularis releases androgens
• The adrenal medulla releases stress hormones

Hormone Receptors on Granulosa and Theca Cells:

• Receptors for LH and FSH are located on granulosa and theca cells.
• LH interacts with theca cells, and FSH interacts with granulosa cells.

Forceful Expiration

• Internal intercostal muscles are involved in forceful expiration.

Testes Covering

• The tunica albuginea covers the testes.

Breath Rhythm

• The ventral respiratory group generates breathing rhythm and is involved in forceful breathing.

Paranasal Sinuses

• The paranasal sinuses are nasal structures that affect taste.
• There are ethmoid, frontal, maxillary and sphenoid sinues

Tropic Hormones.

• Tropic hormones target other endocrine organs.
• Hormone Structures: Steroids, Nonsteroids e.g. proteins, glycoproteins, peptides, amino acid derivatives

Milk Secretion

• The last tubes through which milk flows before it reaches the outside are the lactiferous sinuses.

Pancreas

• Glucagon is associated with the alpha cells of the pancreas.

Carbonic Anhydrase

• The enzyme carbonic anhydrase causes carbon dioxide to react with water.

The Bohr Effect

• According to the Bohr effect, a more acidic pH promotes O2-Hb dissociation

Hormone Function

• Permissiveness occurs when a small amount of one hormone allows a second one to have its full effects. Other hormone interaction types
• Synergistic.
• Antagonistic.

Surfactant

• Surfactant is produced by type II alveolar cells.
• Surfactant reduces surface tension of alveolar fluid, preventing alveoli from collapsing

Gluconeogenesis

• Gluconeogenesis is the conversion of amino acids and glycerol to glucose.

Testis Cells

• Leydig cells are responsible for producing testosterone.
• Sperm development follows the chain Spermatogonia > Primary spermatocytes > Leydig cells

Ovary Structure

• The cortex portion of the ovary contains the ovarian follicles.

Thyroxine Formation

• For the formation of thyroxine to occur, iodine needs to be present.
• thyroid hormones T3 and T4 are Iodinated tyrosines

Posterior Pituitary Gland Function

• The posterior pituitary gland stores and secretes oxytocin and antidiuretic hormone.

Steroid Hormone Function

• Steroid hormones regulate gene expression.

Oocyte Meiosis:

• Oocytes begin meiosis I during fetal development.
• Oocyte meiosis arrests at metaphase II, and completes after sperm penetrates the oocyte

Vocal Chords

• The vocal cords are found in the larynx.

Fertilization

• Fertilization of the oocyte by a sperm usually occurs in the ampulla of the oviduct.