Exam 5: Digestive System Flashcards
The digestive system function…
Ingests food, transports it, and breaks it into smaller components
The digestive system consists of…
Alimentary canal and accessory digestive organs
As food passes through the alimentary canal, accessory digestive organs…
Add substances to assist with the food breakdown
From the mouth to the anus, the tubular alimentary canal exhibits…
Circular and longitudinal muscles
Coordinated rhythmic contractions of the gastrointestinal tract
Peristalsis
Food is broken down…
Mechanically and chemically using enzymes
From the _ to anus, the digestive tract is a
Pharynx, continuous tube which food passes
What allows the digestive tract to move contents in one direction
Circular and longitudinal muscles contracted for peristalsis
Primary muscles of mastication
Temporalis, masseter and pterygoid muscles
Temporalis originates from
Lateral skull
Temporalis inserts on
Coronoid process of mandible
Temporalis acts to
Elevate mandible
Masseter originates from
Zygomatic arch
Masseter inserts on
Lateral surface of mandible and angle
Masseter acts to
Elevate the mandible
Medial and lateral pterygoids originate from the
Lateral pterygoid plate of pterygoid process
Lateral pterygoid inserts on
disc of temporomandibular joint
Medial pterygoid inserts on
Angle of mandible
Medial and lateral pterygoids both work together to
Move mandible side to side for grinding
Muscles of mastication are innervated by…
Mandibular division of trigeminal nerve (V3)
Oral cavity is space between
Dental arches
the space between the dental arches and lips/cheeks
vestibule
the roof of the oral cavity
palate
hard palate is formed by
maxillary and palatine bones.
soft palate is
fibromuscular
Uvula hangs off the
Posterior midline of soft palate
Helps seal off the uvula during swallowing
Nasopharynx
the palatoglossus and palatopharyngeus muscles help move food to the__and form….
pharynx with
swallowing and form a “bed” for the palatine tonsil.
mucosal fold connected to upper lip.
superior labial frenulum
mucosal fold connected to lower lip.
inferior labial frenulum
mucosal fold connected to inferior surface of tongue.
lingual frenulum
Tongue is formed by
instrinsic muscles that can change the shape of the tongue.
extrinsic muscles move the tongue
around in the oral cavity
the largest of the extrinsic muscles is the
genioglossus muscle
The genioglossus muscle extends from the
“genu” of the mandible into the tongue.
Tongue can be divided into the…
body (anterior 2/3) and root (posterior 1/3).
the body of the tongue is covered by mucous membrane with specialized features called
papillae
the root of the tongue has the
lingual tonsil
general sensation from body of the tongue carried by
mandibular division of trigeminal
nerve (V3).
taste from body of the tongue is carried by
facial nerve (CN VII)
general sensation and taste from root of the tongue is carried by the
glossopharyngeal
nerve (CN IX).
muscles of the tongue are innervated by
hypoglossal nerve (CN XII).
strong muscle that protrudes the tongue
genioglossus
genioglossus is often used to tear the integrity of the
hypoglossal nerve.
assists with initial activities of digestion.
saliva
volume of secreted saliva is estimated at
1.0 – 1.5 liters a day.
Percent of saliva that’s water
99.5%
Saliva function
lubricates structures in oral cavity.
amylase in saliva begins to break down
carbohydrates
saliva also contains
antibodies and antibacterial substances
largest of the salivary glands.
parotid glands
parotid gland are near
angle of mandible.
parotid glands transport saliva to oral cavity by
Parotid duct
Parotid glands produce what percent of saliva
25 - 30% of the saliva.
Parotid glands get their parasympathetic innervation from
glossopharyngeal nerve (CN IX)
submandibular glands located in
upper neck, under body of mandible.
submandibular glands transport saliva to oral cavity by
submandibular duct.
submandibular glands produce what percent of saliva
60 – 70% of the saliva.
submandibular glands get their parasympathetic innervation from
facial nerve (CN VII).
sublingual glands located under the
tongue in floor of oral cavity.
sublingual glands produce what percent of saliva
3 – 5% of total saliva
sublingual glands get their parasympathetic innervation from
facial nerve (CN VII)
3 phases of swallowing
Oral preparatory phase, elevation, reset
In the oral preparatory phase of swallowing
the tongue moves food around and muscles of mastication break it down mechanically. Saliva is added to begin chemical breakdown.
In the elevation phase of swallowing
The larynx elevates and the pharynx shortens (and widens) to receive food.
In the reset phase of swallowing
the larynx lowers and pharynx lengthens and becomes more narrow; propels food from the pharynx into the esophagus
What muscles elevate the larynx during the 2nd phase of swallowing
suprahyoid muscles
What are the suprahyoid muscles
Digastric and mylohyoid
pull it down to reset its position during the 3rd phase:
infrahyoid muscles
What are the infrahyoid muscles
sternohyoid and sternothyroid
The esophagus descends along the
Posterior thorax and passes through diaphragm
The esophagus does not
absorb nutrients
Esophagus is composed of what tissue
thick, nonkeratinized stratified squamous epithelium
has elastic fibers to allow distension during swallowing
submucosa
In the esophagus, the muscular layer has
Inner circular and outer longitudinal components
The upper part of the esophagus has
Skeletal muscle (voluntary)
inferior part of esophagus has
smooth muscle (involuntary)
Esophageal sphincter between
Esophagus and stomach
prevent movement of food
from stomach into esophagus
esophageal sphincter
entryway into stomach from esophagus
cardia
dome of stomach.
fundus
large, middle region.
Body
funnel-shaped end of stomach
pyloric region
control food
leaving stomach
pyloric sphincter
lesser curvature
small concavity of right side
greater curvature
large convexity of left side
gastric folds (rugae)
internal folds of stomach (allow expansion)
The stomach is lines with what tissue
simple columnar epithelium with surface mucous cells
receive secretions from gastric glands.
gastric pits
Gastric glands consist of
Chief, parietal, mucous neck, enteroendocrine cells
Chief cells secrete
Pepsinogen and gastric lipases
Pepsinogens break down
Protein
Parietal cells secrete
Intrinsic factor and hydrochloric acid
Binds vitamin B 12
Parietal cells
Mucous neck cells secretes
Acid fluid containing mucin
Enteroendocrine cells secretes
Gastrin to stimulate muscle contractions
The small intestine legnth
20 ft long
In the small intense, what percent of nutrients are absorbed
90%
First part, second, and third part of small intestines
Duodenum, jejunum, ileum
Length of duodenum
10 inches long
Shape of duodenum and cradles what
C shaped and cradles the head of the pancreas
The duodenum receives secretions (bile) from
liver and gallbladder
Receives digestive enzymes from pancreas
Duodenum
How long is the jejunum
7.5 ft
It is the main region of the small intensive for chemical digestion and nutrient absorption
Jejunum
How long is the ileum
10 ft long
Distal end of ileum terminates at the
ileocecal valve
Controls movements of materials into large intestine
Ileum
The small intestine has
Mucosa, muscular layer, and serosa
The mucosa is thrown into
Circular folds
The small intense has finger like villi that
Increase SA for absorption and secretion
The endothelium of the small intestine consists of
Simple columnar epithelia with microvilli and goblet cells
The simple columnar epithelial cells in the small intestine absorb
Nutrients and water
In the center of each villus, there is a
Capillary network and lacteal
Lacteals transport
Lymph and dietary lipids
Intestinal glands contain
Unicellular gland cells and enteroendocrine cells
Secretes hormones in small intestine
Enteroendocrine cells
Can slow movement down of food out of the stomach
Enteroendocrine cells
Submucosal produce an alkaline mucus to protect the
Duodenum from acidic chyme
Large intestine is how long and function
5feet long and absorbs water and ions from remaining digested material
The large intestine consists of the
Cecum, ascending colon, transverse colon, descending colon, and sigmoid colon
Parts of large intestine in order….
Cecum, ascending colon, transverse colon, descending colon, sigmoid colon
Pouch like structure extending inferiorly from the ileoceal valve
Cecum
What is attached to the cecum
Appendix
The ascending colon ascends on the
Right side of the abdomen from cecum to liver
The ascending colon transitions into the __ at the __
Transverse colon at right flexure
Originates at the right colic flexure and courses to the left, inferior to the stomach
Transverse colon
As __ approaches the spleen, it turns inferiorly at the splenic flexure to become the
Transverse colon, descending colon
along the left side of abdomen from left colic flexure to ilium
Descending colon
The sigmoid colon courses over the
Iliac fossa and descends into the pelvis and into rectum
Three external longitudinal bands of smooth muscle are visible in the large intestine
Teniae coli
Function of teniae coli…
Help shorten large intestine during peristalsis
Teniae coli are _ than the length of the large intestine
Shorter
Large intestine forms pouches
Haustra
Internal anal sphincter is __ and under control of __
Smooth muscle and under the control of ANS
External anal sphincter is _ muscle and under control of __
Skeletal muscle, somatic motor system
Mucosa of the large intestine is lined with
Simple columnar epithelium and goblet cells
Simple columnar cells continue to
Absorb nutrients and water
Goblet cells secrete mucus to
Lubricate the undigested material
The mucosa in the large intestine lack
Villi
The muscular layer in the large intestine has a
Inner circular layer and outer longitudinal layer in the form of taniae coli
What’s found in the submucosa of the large intestine
Lymphatic nodules
The reflex center in the brain activates under
Parasympathetics
Parasympathetics cause the internal anal sphincter to __ and the wall of the rectum to __
Relax, contract
Sympathetic store feces by
Relaxing wall of rectum and contracting internal anal sphincter
Parasympathetics release feces by
Relaxing internal anal sphincter and contracting wall or rectum
Outgrowths of the colon mucosa into the lumen
Polyps
Part of the stomach that protrudes through the diaphragm into thorax
Hiatal hernia
Out pocketing of the intestinal wall, usually the large intestine
Diverticulitis
Erosion of the lining of stomach or duodenum
Peptic ulcer
Superior surface of liver is fused to the
Diaphragm above
Large organ located in upper right quadrant of abdomen
Liver
Liver consists of
two major lobes and two minor lobes
Separates right and left lobes and attaches liver to abdominal wall
Falciform ligament
During fetal circulation, the round ligament was a
Functional blood vessel that carries oxygenated blood from placenta
At The inferior aspect of the falciform ligament there is a dense cord of tissue called
Round ligament of liver
Function of liver
Remove harmful substances from food being absorbed by the GI tract and hepatic portal vein
Liver produces
Bile to break down fats
Bile is transported to the
Duodenum
Gallbladder function
Stores bile
Liver is considered to be an
Exocrine gland
Right and left lobes of liver seen
Anteriorly
Liver secretes bile into
Hepatic ducts
Gallbladder secretes bile into the
Cystic duct
What forms the common bile duct
Hepatic and cystic duct
Pancreatic duct joins the common bile duct to empty into
Duodenum
Pancreas has what function
Exocrine and endocrine
The exocrine part of the pancreas consists of
Acinar cells
synthesize and secrete
pancreatic juice to help with digestion
Acinar cells
the pancreatic juice consists of
mucin and digestive enzymes
the endocrine part of the pancreas includes
islet cells which produce insulin
The serous membrane that lines the abdominal cavity is called
Peritoneum
as the abdominal organs grow into the abdominal cavity, they acquir
a covering of
peritoneum.
when peritoneum is found on the surface of an abdominal organ, it is called
visceral
peritoneum.
when peritoneum is found on the inner wall of the abdominal cavity, it is called
parietal
peritoneum.
when the peritoneum sandwiches the neurovascular supply of “intraperitoneal” organs, it is called
mesentery
certain parts of the digestive tract (such as the small intestine, transverse colon and
sigmoid colon) grow into the abdominal cavity such that the
peritoneum behind them “collapses” on the nerves and blood vessels traveling to them.
Has mucosa that has circular folds and villi
Ileum
3rd phase of swallowing what happens
Larynx moves down
