RAT 15 Flashcards
what are the three barriers that separate the blood in the glomerulus from the capsular space?
- fenestrated glomerular capillary endothelial cells
- basal lamina
- podocytes (visceral layer of the glomerular capsule)
what are the three types of capillaries?
- fenestrated
- continuous
- sinusoid
what type of capillary is the glomerulus?
fenestrated
what can pass through a fenestrated capillary?
- blood
- fluid
- waste
what cannot pass through a fenestrated capillary?
plasma proteins
what is the glomerular filtration rate (GFR)?
the rate at which filtrate is produced in the glomeruli of the kidneys
how much filtrate is produced in one day?
180 liters of filtrate
what is hydrostatic pressure?
the force of a fluid on the wall of its container
what is colloid pressure?
the pressure created by proteins (primarily albumin) in the plasma
what is net filtration pressure?
determines the direction of water between the capillaries and the interstitial fluid
what is name and abbreviation for the blood hydrostatic pressure (blood pressure) in the glomerulus? which direction is this force?
- glomerular hydrostatic pressure
- GHP
- through the filtration membrane
why is GHP higher than a typical systemic capillary?
because blood leaving such a capillary bed enter a low-resistance venule, where as blood leaving the glomerulus enters a high-resistance efferent arteriole
what is the term and abbreviation for the colloid osmotic pressure in the glomerulus? which direction is this force?
- glomerular colloid osmotic pressure
- GCOP
- opposes filtration, drawing water into the capillaries by osmosis
what is the term and abbreviation for the hydrostatic pressure in the capsular space? which direction is this force?
- capsular hydrostatic pressure
- CHP
- opposes filtration, pushes water into the glomerular capillaries
what is the name for the force that combines the three forces (GHP, GCOP, CHP)?
net filtration pressure (NFP)
which filter more fluid; systemic capillaries or glomeruli?
glomeruli
a high pressure gradient in the glomerulus will lead to _______ filtration
more
a low pressure gradient in the glomerulus will lead to __________ filtration
less
what is a way to easily adjust the pressure gradient in the glomerulus?
change diameter of afferent and efferent arterioles
in the analogy what is the afferent arteriole? the glomerulus? the efferent arteriole?
- faucet
- basin
- drainpipe
how does vasoconstriction of the afferent arteriole impact filtration?
allows less blood flood into the glomerulus, decreases GHP and GFR
how does vasoconstriction of the efferent arteriole impact filtration?
causes blood to back up within the glomerulus, increases GHP and GFR
how does vasodilation of the afferent arteriole impact filtration?
“turns up the faucet”
- increases GHP and GFR
how does vasodilation of the efferent arteriole impact filtration?
allows increased flow out of the glomerulus, decreases GHP and GFR
does the GFR rate change every time the systemic blood pressure changes? why or why not?
no because of autoregulation
where is ANP produced?
atria
what is the stimulus for the release of ANP?
volume of blood in the atria increases
what impact does ANP have on the GFR? how does that impact blood pressure?
- increases GFR
- lower BP
by which mechanism does ANP change the GFR?
dilating the afferent arterioles and constricting the efferent arterioles
what is the primary function of the RAAS?
maintaining systemic blood pressure
renin is an enzyme. what reaction does it catalyze? where is it produced?
- conversion of angiotensinogen to angiotensin-I
- JG cells
where is angiotensinogen produced?
liver
what reaction does angiotensin converting enzyme (ACE) catalyze? where is it produced?
- angiotensin-I to angiotensin-II
- lungs
what are the effects of angiotensin-II (A-II)?
- promotes vasoconstriction of efferent arterioles
- promotes vasoconstriction of systemic blood vessels
- promotes reabsorption of sodium and calcium ions from the proximal tubule, and water follows
what is renal failure?
condition where the kidneys are unable to perform their vital functions
what is uremia?
severe renal failure where FR is less than 50% of normal
what three branches of the abdominal artery supply blood to the abdominal digestive organs?
- celiac trunk
- superior mesenteric artery
- inferior mesenteric artery
what vessel drains blood from the digestive organs and where is the blood delivered?
- hepatic portal vein
- inferior vena cava
why is motility of the digestive system so important?
we do not want things to remain stagnant within the gut
which branch of the ANS tends to increase motility?
parasympathetic
which branch of the ANS tends to decrease motility?
sympathetic
describe the enteric nervous system (ENS)
a self-contained branch of the autonomic NS and regulates secretion and motility of the digestive organs
what is a lumen?
the space enclosed by a hallow organ
list the four layers found in most regions of the alimentary canal
- mucosa
- submucosa
- muscularis externa
- serosa or adventitia
what are the three components of the mucosa?
- muscularis mucosae
- lamina propria
- epithelium
what type of epithelium is found from the stomach to the end of the large intestine?
simple columnar epithelium
what is a plexus?
a cluster of nerves
where is the submucosal plexus located?
submucosa
where is the myenteric plexus located?
muscularis externa
describe the arrangement of the smooth muscle layers in the muscularis externa
inner circular and outer longitudinal layers
when is the outermost layer called the serosa?
within the peritoneal
when is the outermost layer called the adventitia?
organs outside the peritoneal cavity
what is a bolus?
a moistened, partially digested ball of ingested food that is swallowed and transported to the stomach via the pharynx and esophagus
what muscle largely forms the cheeks?
buccinator muscles
what tissue lines the cheeks?
stratified squamous nonkeratinized epithelium
what is the labial frenulum?
narrow band of mucosa; attaches the internal surface of the upper and lower lips to the gums of the midline
where is the vestibule located?
between the teeth and gums and the internal space of the lips and cheecks
where is palate located?
roof of the mouth
what are the two regions of the palate?
hard palate and soft palate
what is the uvula? what is its function?
- a portion of the soft palate suspended in the posterior oral cavity
- seals off the nasopharynx during swallowing to prevent food and liquid from entering the nasal cavity
what is the term for a tooth socket?
alveoli
what holds teeth in place?
periodontal ligament
what is mastication? is it mechanical or chemical digestion? how does it aid in chemical digestion?
- chewing
- mechanical
- giving digestive enzymes more places to catalyze their reactions
define crown
the visible portion above the gum line
define root
embedded within the alveolus
define enamel
outer layer of hard mineralized substance
define pulp
soft, inner gelatinous substance
define cementum
mineralized bone like tissue; half calcium and half organic compounds
define dentin
inner mineralized material of a tooth composed largely of calcium hydroxyapatite crystals
define pulp cavity
house the inner pulp
define root canal
how the pulp cavity extends into the root
what is the lingual frenulum?
prevents the tongue from moving too far posteriorly
what are papillae?
finger-like protrusions on the surface of the tongue, some contain taste buds
what are extrinsic muscles?
control the position of the tongue
what are intrinsic muscles?
control the shape and size of the tongue
name and describe the location of the three pairs of salivary glands and their ducts
- portal glands: over the masseter muscle just anterior to the ear
- submandibular glands: just medial to the inferior portion of the body of the mandible
- sublingual glands: inferior to the tongue
what are the two types of cells that secrete saliva and how do their secretions differ?
- serous cells: secrete water-based fluid with enzymes and other solutes
- mucous cells: secrete mucous
what enzyme is found in saliva? where does it break down?
- salivary amylase
- large polysaccharides
what else if found in saliva and what is their function?
- lysozymes: catalyzes perforation of bacterial plasma membranes
- secretory IgA: bind specific antigens on pathogens
- bicarbonate ions: neutralize any acid
what is the function of saliva?
- moistening, lubricating, cleansing the oral mucosa
- mechanical and chemical digesiton
what type of saliva is stimulated by the parasympathetic nervous system? what can trigger this reflex?
- serous saliva
- the smell or taste of food
what type of saliva is stimulated by the sympathetic nervous system?
mucous saliva
what are the three divisions of the pharynx?
- nasopharynx
- oropharynx
- laryngopharynx
what divisions of the pharynx are apart of the alimentary canal?
oropharynx and laryngopharynx
what type of tissue lines the oropharynx and laryngopharynx?
stratified squamous epithelium
what muscles help propel food through the pharynx?
upper, middle, and lower pharyngeal constrictor muscles
describe the location of the esophagus
posterior to the trachea
what type of tissue lines the esophagus?
stratified squamous nonkeratinized epithelium
what glands are found in the esophagus?
esophageal glands
what is the function of esophageal glands?
secrete mucus to lubricate the bolus as it passes through the esophagus
what is the name of the sphincter at the beginning of the esophagus?
upper esophageal sphincter
list two names for the sphincter at the end of the esophagus
- gastroesophageal and lower esophageal sphincter
what is the esophageal hiatus?
opening in the diaphragm through which the esophagus and vagus nerve pass
what is deglutition?
a specialized type of propulsion that pushes a bolus of food from the oral cavity through the pharynx and esophagus to the stomach
what is a bolus?
a moistened, partially digested ball of ingested food that is swallowed and transported to the stomach via the pharynx and esophagus
what controls the process of swallowing?
coordinated action of the upper alimentary canal (soft palate, pharynx, esophagus), tongue also plays a role
describe the three phases of swallowing
- voluntary
- pharyngeal
- esophageal
describe the two curvatures and the five regions of the stomach
- greater curvature: convex left side
- lesser curvature: concave right side
- 5 regions: cardia, fundus, body, pyloric, pylorus
what are rugae?
fold that allow the stomach to expand
what are the four tissue layers of the stomach?
- mucosa
- submucosa
- muscularis externa
- serosa
how does the muscularis externa of the stomach differ from the typical arrangement in the digestive tract?
there is an additional inner layer of smooth muscle in the stomach’s body with its fibers oriented obliquely
what is chyme?
a liquid mixture that results from the stomach churning a bolus and mixing it within gastric juice
what are gastric pits?
deep structures formed by mucosa of the stomach that is heavily indented
what type of epithelial tissue lines the stomach?
simple columnar epithelium
what cells produce mucus that coat the stomach?
columnar epithelium cells
what causes a gastric ulcer?
decrease in the amount of mucus secreted by columnar epithelium cells
what are gastric glands?
multiple branched glands found at the base of gastric pits
name four cells found in gastric glands and their products
- mucous neck cells: acidic mucus
- parietal cells: hydrochloric acid and intrinsic factor
- chief cells: pepsinogen
- diffuse neuroendocrine system cells: gastrin and histamine
describe the three primary functions of the stomach. what function is notably absent from this list?
- secretion, propulsion, digestion
- absorption of digested nutrients
what four processes occur in the small intestine?
- secretion
- digestion
- absorption
- propulsion
what is the name of the cells that line the lumen of the small intestine and what do they produce?
- enterocytes
- multiple digestive enzymes, hormones, and mucus
describe the three divisions of the small intestine
- duodenum: c-shaped
- jejunum: middle portion
- ileum: final segment
what are the three features that increase the surface area of the small intestine? which can be seen with the naked eye? which forms a brush boarder?
- circular fold, villi, microvilli
- circular folds
- microvilli
what are the functions of the large intestine?
- critical for maintaining fluid, electrolyte, and acid-base homeostasis
- secretion (mucus form primarily)
- propulsion
- defecation
- houses many good bacteria
what are the three segments of the large intestine?
cecum. colon, rectum
what are the regions of the colon?
- ascending
- descending
- transverse
- sigmoid
name the flexures of the colon
- hepatic flexures: right colic
- splenic flexures: left colic
name the sphoncters of the anus
internal and external anal sphincters
what is unique about the muscularis externa of the large intestine?
longitudinal layer is not continuous throughout most of its length
what is a haustrum?
pockets due to constant tension
what is a epiploic appendage?
fat filled pouches of the serosa of the large intestine
what are “normal flora” or “gut flora”
consist of ~ 500 different bacterial species that coexist with humans in a symbiotic relationship
list four benefits of glut flora
- produce vitamins
- metabolize undigested materials
- deter the growth of harmful bacteria
- stimulate the immune system
