Biology Final End of Year Exam Flashcards
Histology of the alimentary canal
Lumen outward - Muscosa, sub mucosa, muscularis externa, serosa
4 tunics of the GI Tract
Lumen outwards :
Mucosa
Sub mucosa
muscularis externa, serosa
Lumen outwards :
Mucosa
Sub mucosa
muscularis externa, serosa
Mucosa : absorption of end products
secretes mucus
protection against infectious diseases
Lining epithelium :
Mucus that protects the organ from digesting itself
Helps food along the tract
Lamina propria:
Loose areolar and reticular connective tissue
nourishes the epithelium and absorbs nutrients
Contains Lymph nodes important for defense against bacteria
muscularis mucosae : Smooth muscle cells that produce local movements of mucosa
Lamina propria
Loose areolar and reticular connective tissue
nourishes the epithelium and absorbs nutrients
Contains Lymph nodes important for defense against bacteria
submuscosa
dense connective tissue containing elastic fibres, blood and lymphatic vessels, lymph nodes and vessels
Muscularis externa :
responsible for the segmentation and peristalis
serosa
the protective visceral peritoneum
esophages has what type of call connective tissue
stratifies squamous epithelium
Small Intestine:
The epithelium of the mucosa is made up of:
Absorptive cells and goblet cells
▪ Enteroendocrine cells
▪ Interspersed T cells called intraepithelial
lymphocytes (IELs)
▪ IELs immediately release cytokines upon
encountering Ag
Cells of intestinal crypts secrete intestinal juice
▪ Peyer’s patches are found in the submucosa
▪ Brunner’s glands in the duodenum secrete alkaline
mucus
Bile leaves the liver via:
Bile ducts, which fuse into the common hepatic
duct
▪ The common hepatic duct, which fuses with the
cystic duct
▪ These two ducts form the bile duct
Chemical Digestion: Carbohydrates
Absorption: via cotransport with Na+, and facilitated
diffusion
▪ Enter the capillary bed in the villi
▪ Transported to the liver via the hepatic portal vein
▪ Enzymes used: salivary amylase, pancreatic
amylase, and brush border enzymes
Chemical Digestion: Fats
Absorption: Diffusion into intestinal cells where
they:
▪ Combine with proteins and extrude chylomicrons
▪ Enter lacteals and are transported to systemic
circulation via lymph
▪ Glycerol and short chain fatty acids are:
▪ Absorbed into the capillary blood in villi
▪ Transported via the hepatic portal vein
▪ Enzymes/chemicals used: bile salts and pancreatic
lipase
Fatty Acid Absorption
Fatty acids and monoglycerides enter intestinal cells
via diffusion
▪ They are combined with proteins within the cells
▪ Resulting chylomicrons are extruded
▪ They enter lacteals and are transported to the
circulation via lymph
Respiratory Membrane
▪ This air-blood barrier is composed of:
▪ Alveolar and capillary walls
▪ Alveolar walls:
▪ Are a single layer of type I epithelial cells
▪ Permit gas exchange by simple diffusion
▪ Secrete angiotensin converting enzyme (ACE),
(has a role in regulation of BP)
▪ Type II cells secrete surfactant (to prevent surface
tension)
Alveoli
Surrounded by fine elastic fibers
▪ Contain open pores that:
▪ Connect adjacent alveoli
▪ Allow air pressure throughout the lung to be
equalized
▪ House macrophages that keep alveolar surfaces
sterile
Gross Anatomy of the Lung
Lungs occupy all of the thoracic cavity except the
mediastinum
▪ Root – site of vascular and bronchial attachments
▪ Costal surface – anterior, lateral, and posterior
surfaces in contact with the ribs
▪ Apex – narrow superior tip
▪ Base – inferior surface that rests on the diaphragm
▪ Hilus – indentation that contains pulmonary and
systemic blood vessels
Pulmonary Ventilation
A mechanical process that depends on volume
changes in the thoracic cavity
▪ Volume changes lead to pressure changes, which
lead to the flow of gases to equalize pressure
Nasal mucosa & Nasal Cavity
pseudostratified ciliated colomnar epithelium with goblet cells
Kidney Functions
Filter 200 liters of blood daily, allowing toxins,
metabolic wastes, and excess ions to leave the body
in urine
▪ Regulate volume and chemical makeup of the blood
▪ Maintain the proper balance between water and
salts, and acids and bases
Cortex –
Medulla –
Cortex – the light colored, superficial region
▪ Medulla – exhibits cone-shaped medullary (renal)
pyramids
Pyramids are made up of parallel bundles of
urine-collecting tubules
▪Renal columns are inward extensions of cortical
tissue that separate the pyramids
▪ The medullary pyramid and its surrounding
capsule constitute a lobe
The Nephron
Nephrons are the structural and functional units that
form urine, consisting of:
▪ Glomerulus – a tuft of capillaries associated with a
renal tubule
▪ Glomerular (Bowman’s) capsule – blind, cupshaped end of a renal tubule that completely
surrounds the glomerulus
Proximal convoluted tubule (PCT
Reabsorbs water and solutes from filtrate and
secretes substances into it
Blood pressure in the glomerulus is high because:
Arterioles are high-resistance vessels
▪ Afferent arterioles have larger diameters than
efferent arterioles
▪ Fluids and solutes are forced out of the blood
throughout the entire length of the glomerulus
Urine formation and adjustment of
blood composition involves three
major processes
Glomerular filtration
▪ Tubular reabsorption
▪ Secretion
Factors governing filtration rate at the capillary bed are
Total surface area available for filtration
▪ Filtration membrane permeability
▪ Net filtration pressure
Chemical Composition of Urine
Urine is 95% water and 5% solutes
▪ Nitrogenous wastes include urea, uric acid, and creatinine
▪ Other normal solutes include:
▪ Sodium, potassium, phosphate, and sulfate ions
▪ Calcium, magnesium, and bicarbonate ions
▪ Abnormally high concentrations of any urinary constituents may
indicate pathology
Ureters
Slender tubes that convey urine from the kidneys to the bladder
▪ Ureters enter the base of the bladder through the posterior wall
▪ This closes their distal ends as bladder pressure increases and prevents
backflow of urine into the ureters
▪ Ureters actively propel urine to the bladder via response to smooth
muscle stretch
Upon ejaculation the epididymis
Upon ejaculation the epididymis contracts, expelling sperm into the
ductus deferens
