Anatomy and Physiology of the Immune System

Lymphoid System

• Undifferentiated cells around the wall of capillaries are called Pericytes.
• Thymus dependent zones are present in the Paracortex of the lymph node.

Thymus

• The thymus is an organ that has both lymphoid and endocrine functions.

Tonsils

• The epithelium layer of the pharyngeal tonsil is Pseudostratified columnar ciliated epithelium.
• The Palatine tonsil is located in the Oropharynx.

Skin

• Langerhans cells are a type of macrophage found in the skin.
• Merkel cells are mechanoreceptors.
• Apocrine sweat glands are found in the axilla.

Respiratory System

• The layer under the epithelium of the trachea is Connective tissue.
• Type II pneumocytes secrete Surfactant.
• Type I pneumocytes are Simple cuboidal epithelium.

Blood Air Barrier

• The blood air barrier does not include the Cytoplasm and basement membrane of the Type II pneumocyte.

Tongue

• Filiform papillae do not contain taste buds.
• The epithelium layer of the dorsal surface of the tongue is Stratified squamous epithelium.
• Taste buds contain Neuro-epithelium.

Esophagus

• The middle third of the esophagus has both Skeletal and smooth muscle.

Intestine

• Enteroendocrine cells have an Infraneuclear nucleus.
• Paneth cells are found in Intestinal crypts.
• Caveolate cells are chemoreceptors in the small intestine.
• Peyer's patches are found in the Ileum.

Salivary Glands

• The major acini in the sublingual salivary gland are Mucous acini.
• Centroacinose cells belong to the Intercalary ducts.
• Intralobular ducts are secretory ducts.

Liver

• The liver acinus is Diamond-shaped.
• Von Kupffer cells stain with Trypan blue.
• Hepatocytes facing bile canaliculi have Short microvilli.

Clara Cells

• Clara cells have a characteristic dome-shaped apical end that projects into the lumen.

Adrenal Gland

• Aldosterone is secreted by Zona granulosa cells.
• Mesangial cells are located in the matrix between glomerular cells.

Pituitary Gland

• Somatotrophs secrete growth hormone.

Testis

• Sertoli cells form the blood-testis barrier.

Kidney

• Bile canaliculi are present between the rows of liver cells.
• Renal columns are located between renal pyramids.
• The outer epithelium of the Bowman's capsule is Simple squamous epithelium.
• The epithelium layer of the prostatic part of the urethra is Transitional epithelium.

Suprarenal Gland

• Spongiocytes belong to the Zona fasciculata.
• Pheochromocytes belong to the Suprarenal medulla.

Thyroid Gland

• Thyrotrophs are basophiles.
• Corticotrophs secrete ACTH.
• Pars intermedia secretes melanocytes stimulating hormones.

Pineal Body

• Pineal body cells secrete melatonin.

Reproductive System

• Parafollicular cells contain C-cells.
• The capsule surrounding the testis is the Tunica vaginalis.
• Spermatogenic and Sertoli cells form seminiferous tubules.
• The epithelium lining the epididymis is Pseudostratified columnar ciliated epithelium.
• Zona pelucida has a pinkish-red ring.
• Human Chorionic gonadotropin hormone rescues the corpus luteum from degeneration.
• Peg cells secrete fluids containing nutrients for the oocyte and promote capacitation.