lab 8 - excerices 38

other name for digestive system

alimentary canal

what do the accessory organs do?

secret substances necessary for digestion, yet do not come into direct contact with food

functions of the digestive system

ingestion of food, the physical breakdown of food, the chemical breakdown of food, food storage, food and water absorption, vitamin synthesis, and the elimination of in digestible material

what’s another name for the lips?

labia

what’s another name for the membranous structure that keeps the lips adhered to the gums

labial frenulum (gingivae)

what forms the roof of the oral cavity

Hard and soft palates

what is the hard palate composed of?

palatine Process of the maxilla and Palatine bones

what is the soft pallet composed of?

Connective tissue and a mucus membrane

what is the function of the uvula?

Prevent food and liquid from moving into the nasal cavity during following and keeps food in the oral cavity during chewing

what is the oral cavity lined with?

non-keratinized stratified squamous epithelium, which protects the underlying tissue from abrasion

what is one of the major muscles of the tongue

genioglossus

what is the major functions of the tongue?

Speech taste in the movement of food toward the teeth for chewing and swallowing, Acts as a pistol to propel food to the oropharynx

what is the tongue held down to the floor of the mouth by?

A thin mucus membrane called the lingual frenulum

what are the four types of papillae?

foliate (leaf shaped), fungiform (mushroom shaped), filiform (threadlike) and vallate (large)

what are the muscles of mastication?

masseter, temporalis, ptyerygoids, digastric, and platysma muscles

what is involved in the closing of the draw?

masseter and temporalis

what is involved in the sideways, grinding action of the molar and molar teeth?

ptertgoid muscles

what muscles are involved in opening the mandible

digastric and platysma

what are the parts of a tooth?

Crown, neck, root

what are the three layers of the tooth?

Outer Layer is the enamel, inside the layer is the Dentin (which is made of bone like material), And the innermost portion consist of the pulp cavity, which leads to the root canal

order the nerves in blood vessels enter the tooth

through the apical foreman

what are the teeth in?

Depressions in the mandible or maxilla called alveolar sockets, anchored to the bone by periodontal ligaments

what are the four types of teeth in the adult mouth?

Incisors 8, canines (cuspid) 4, Premolars (bicuspid) 8, And molars 12

how many cups do molars have?

3-5

what are the two sets of human teeth?

The primary or deciduous Which are replaced by the secondary or permanent teeth

what are the types of deciduous teeth?

There are 20 of them, no pre-molar, and only eight molar

How many premolars and molar teeth do adults have?

8 premolar and 12 molar

where does the nasopharynx begin?

At the internal nares and ends at the soft palate

what is the oropharynx composed of?

Non-keratinized stratified squamous epithelium; A common pathway for food liquids and air

what are the muscles around the wall of the oropharynx?

pharyngeal constrictor muscles; in charge of swallowing

what is the function of the esophagus

conducts food and liquid from the oropharynx, Through the diaphragm, and into the stomach

at what level of the spine does the esophagus begin?

The sixth cervical vertebrae

what is a lump of food called?

bolus

once food enters the esophagus, what move it towards the stomach

skeletal muscle

what is the middle portion of the esophagus composed of?

both skeletal and smooth muscle, whereas the interior portion of the esophagus is made of smooth muscle

what is the process of the esophagus contracting in moving food?

parastalsis

what are the two layers of the esophagus?

The inner epithelial lining of stratified, epithelium, and an outer connective tissue layer called the adventitia

what is the space in the esophagus that the food passes through?

the lumen, which continues through the digestive tract

what does the inferior portion of the esophagus have?

in esophageal sphincter, which prevents backflow of stomach acids

what causes Gerd?

when stomach contents pass superiorly through the esophageal sphincter and irritate the esophageal mining

what is the membrane lining the outer surface of the digestive tract?

visceral peritoneum (serosa)

what does the serosa turn into?

It continues as a double folded membrane, the mesentery, which attaches a digestive tract to the back of the body wall

what is the mesenterycontinuous with?

The membrane on the inner side of the body wall, where it becomes the parietal peritoneum

what are the three layers of the stomach, small intestine, and large intestine?

The innermost layer is the mucosa, Which consists of epithelium closest to the lumen, A connected tissue layer called the lamina propria, and an outer, muscular layer called the muscularis mucosae

what are the layers of the stomach, small intestine and large intestine called together

The mucus membrane

what is the layer above the mucus membrane?

The submucosa, which is made of connective tissue and contains many blood vessels

what layer is after the submucosa?

The muscularis, which is typically made of two or three layers of smooth muscle

what is the function of the muscularis?

propels material through the digestive tract and mixes ingested material with digestive juices

what is the outermost layer called?

the serosa, or visceral peritoneum, in this layer is closest to the body cavity

what is the pH of the stomach?

It can be as low as a one or two

how long does chyme remain in his stomach?

Long enough for the acids to denature proteins and enzymes and reduce proteins to shoulder fragments

what is the upper portion of the stomach?

cardia

what is the portion of the stomach that extends superiorly as a domed section called?

fundus

what is the terminal portion of the stomach, closest to the small intestine?

pyloris

what are the two sections of the pylorus?

The expanded area is called the antrum and the narrowed region is called the pyloric Canal

what is the opening to the duodenum controlled by

pyloric sphincter

what is the left and right side of the stomach called?

The greater curvature and the lesser curvature

what are the series of folds on the inner surface of the stomach called?

rugae; allow for significant expansion of the stomach

what are the contents of the stomach held by?

The esophageal sphincter prevents stomach contents from removing into the esophagus in the pyloric sphincter prevents the premature release of stomach contents into the small intestine

what are the inner lining of the stomach and where they found?

Gastric glands, found in the mucosa layer of the stomach

what are the three layers of the mucosa

The epithelial layer, the lamina propria, and the muscular mucosa

what does the epithelial layer of the mucosa consist of?

Simple columnar epithelium, as well as specialized cells, such as surface mucus cells, chief cells, in parietal cells

what does each cell of the epithelial layer secret?

Surface mucus Cell secrete mucus, chief secrete pepsinogen, and parietal cells secrete HCL

what do parietal cells contain?

Orange stained granules

what happens when Pepsinogen comes in the compact with HCI

it activates the enzyme Pepsin

what are the three layers of the muscularis layer Of the stomach?

An inner oblique layer, a middle circular layer, and an outer longitudinal layer

what does the muscularis layer do?

moves chyme form the stomach through the pyloric sphincter and into the small instestine

what is the serosa composed of?

A thin layer of connective tissue in simple squamous epithelium

approximately how long is the small Intestine?

5 meters; 3 to 4 cm in diameter when empty

what is the primary function of The small intestine

nutrient absorption

what is the first part of a small intestine?

duodenum; approximately 25 cm long

what is the function of the duodenum?

receives fluid from both the pancreas and and the gallbladder

what is the junction between the duodenum and the jejunum called?

duodenojejunal flexure

what is the second part of the small intestine

jejunum (approximately 2 m long)

what is the terminal portion of the small intestine?

ileum, approximately 3 m long

what is the closure between the small and large intestine called?

ileocecal valve

what distinguishes the small intestine in comparison to the stomach and large intestine?

villi; fingerlike projections that increase surface area of the mucosa

what does each villi have?

blood vessels that transports sugars and amino acids form the intestine to the liver

what do villi also contain?

lacteals; which transport fatty acids via lymphatics to the venous system

what does the inner lining of the small intestine consist of?

simple columnar epithelium with goblet cells

what distinguishes the three sections of the small intestine?

the duodenum has duodenal glands in the portion of the mucosa away from the lumen

what distinguishes the ileum?

the presence of aggregated lymph nodules or peyer patches in the mucosa and submucosa

what is the function of peyer patches?

lymphatic nodules that produce lymphocytes for the protection of the body from the bacterial flora in the lumen of the small intestine

what is the size of the large intestine?

7 cm in diameter and 1.4 m

what is the function of the large intestine

absorption of water and formation of feces

what is the mucosa of the large intestine made of?

simple columnar epithelium with a large number of goblet cells

where does the ascending colon become the transverse colon?

right colic (hepatic) flexure

where does the transverse colon become the descending colon?

left colic (splenic) flexure

what causes hemorrhoids?

the rectum has superficial veins in its wall called hemorrhoidal veins that can enlarge

what is the first unique feature of the large intestine?

the longitudinal muscle is not a continuous sheet but is located along the length of the large intestine as three bands called teniae coli

what do teniae coli do?

contract and form pouches or pickers in the intestinal tract called haustra

what is another unique feature of the large intestine?

fat lobules, or omental appendages

how does fecal matter pass through the large intestine?

peristalsis and stored in the rectum and sigmoid colon

how is the histology of the large intestine distinguished from the stomach and small intestine?

small intestine: absence of villi

stomach: presence of a large number of goblet cells

what is the function of the salivary glands?

secrete saliva into the oral cavity

what is saliva made of?

watery secretion that contains mucus, a protein lubricant, and salivary amylase, a starchy digestive enzyme

how much saliva does an average adult secrete per day?

1 to 1.5 liters

what is the most superior pair of salivary glands?

parotid glands; located just anterior the the ears

• each gland secretes saliva through a parotid duct, a tube that traverses the buccal region and enters the oral cavity just posterior to the upper second molar

what are the next pair of salivary glands?

submandibular glands; located medial to the mandible on each side of the face; secrete saliva into the oral cavity by a single duct in each side of the oral cavity inferior to the tongue

what’s the last pair?

sublingual glands; located inferior to the tongue and open into the oral cavity by several ducts