A&P2 Exam2 Ch17

A comprehensive set of flashcards designed to cover essential terms and concepts from Chapter 17 of the Digestive System.

Digestion

The mechanical and chemical breakdown of foods into forms that cell membranes can absorb.

Digestive System

Consists of the alimentary canal and accessory organs

Alimentary Canal

A continuous tube running from the mouth to the anus, consisting of mouth, pharynx, esophogus, stomach, small & large intestine, and anal canal

salivary glands, liver, gallbladder, pancreas

What are the 4 accessory organs of the digestive system?

1. mucosa

2. submucosa

3. muscularis

4. serosa

What are the 4 layers of the alimentary canal wall? (deep to superficial)

Serosa

The outer layer of the alimentary canal that provides protection and lubrication; composed of epithelium & connective tissue

Mucosa

The innermost layer of the alimentary canal responsible for protection, secretion, and absorption; composed of epithelium, connective tissue, smooth muscle

Submucosa

A layer that nourishes surrounding tissues and transports absorbed materials; composed of loose connective tissue, blood vessels, lymphatic vessels, & nerves

Muscularis

Layer of smooth muscle that facilitates movements of the tube and its contents; composed of smooth muscle cells in circular and longitudinal groups

mixing movements & propelling movements

What are the 2 movements of the Alimentary canal wall?

mixing movements

muscle in small sections contracts rhythmically; doesn’t move materials in one direction; EX: segmentation in small intestine, churning in stomach

propelling movements

moves materials in one direction; peristalsis

peristalsis

ring of contraction progresses down tube; propels food particles down the tract in wavelike motion

submuscosal plexus

alimentary tube nerve plexus that controls secretions of GI tract

Myenteric plexus

An alimentary tube nerve plexus that controls GI motility.

generally increases activities (through vagus nerve or sacral region of spinal cord)

What does parasympathetic impulses generally do for the GI tract?

usually inhibits digestive activities

What does sympathetic impulses generally do for the GI tract?

Enteroendocrine Cells

Cells in the stomach and small intestine that secrete chemical messengers to regulate GI organs and processes.

mouth

first part of alimentary canal; ingests food; mastication; organ of speech and sensory reception; includes oral cavity & vestibule

Mastication

The mechanical breakdown of food into smaller particles by chewing.

cheeks

form the lateral walls of the mouth; contains muscles for facial expression & chewing; inner lining of stratified squamous epithelium (moisture)

lips

highly mobile structures that surround the mouth opening; sensory receptors judge temp. & texture of food; boundary b/t skin and mucous membrane inside mouth

tongue

thick, muscular organ that occupies the floor of mouth, and nearly fills oral cavity when mouth is closed

Lingual Frenulum

tissue that connects the tongue to the floor of the mouth.

papillae

projections that move food, contain taste buds

lingual tonsils

lymphatic tissue masses on root of tongue

palate

forms roof of oral cavity; consists of hard palate & soft palate; includes palatine tonsils and pharyngeal tonsils

Palatine Tonsils

Lymphatic tissue masses located on the sides of the tongue.

pharyngeal tonsils (adenoids)

masses of lymphatic tissue in posterior wall of pharynx

alveolar processes of mandibular and maxillary bones

Where do teeth develop?

primary teeth & secondary teeth

What are the 2 sets of teeth called?

primary teeth

20 of them; replaced by secondary teeth

secondary teeth

32 of them

incisors

kind of teeth made for biting, front teeth

canines

kind of teeth made for grasping; cone shaped located next to incisors, pointed for tearing food.

bicuspids

kind of teeth made for grinding food

crown

part of tooth that projects beyond gum

root

part of tooth that is anchored to alveolar process of jaw

enamel

part of tooth that covers crown

dentin

part of tooth that is living cellular tissue

root canal

part of tooth where blood vessels and nerves reach cavity

cementum

part of tooth that encloses root

periodontal ligament

part of tooth that attaches tooth to jaw

Salivary Glands

Glands that secrete saliva to moisten food, dissolves food (to taste) containing enzymes for digestion (carbohydrate dige

serous cells & mucous cells

What are the 2 types of salivary secretory cells?

serous cells

salivary secretory cell that produces a water fluid, containing a digestive enzyme called salivary amylase

Salivary Amylase

An enzyme in serous saliva that splits starch and glycogen into disaccharides

mucous cells

salivary secretion cell that secretes mucus; mucus binds food particles and lubricates food while swallowing

small quantity of viscous saliva (which prioritizes protecting mouth→ fight or flight)

What does the sympathetic system innervate salivary glands to secret?

large quantity of water saliva; activated with pleasant food → inactivaded with unpleasant food

What does the parasympathetic system innervate salivary glands to secret?

parotid glands

glands located anterior to ear, uses parotid ducts to deliver clear, watery serous fluid to mouth; rich in salivary amylase

submandibular glands

located in floor of mouth; ducts open inferior to tongue; releases serous fluid w/ some mucus; more viscous than parotid secretion

sublingual glands

located in floor of mouth inferior to tongue; uses many separate ducts; releases primarily thick. stringy mucus

pharynx

connects nasal and oral cavities with larynx and esophagus; includes 3 regions

nasopharynx, oropharynx, laryngopharynx

What are the 3 regions of the pharynx?

nasopharynx

posterior to nasal cavity; air passage; contain openings to auditory tubes

oropharynx

posterior to oral cavity; air and food passage

laryngopharynx

posterior to larynx; passageway to esophagus

1. the tongue forces food into pharynx

2. soft palate, hyoid bone, & larynx are raised, tongue is pressed against the palate, epiglottis closes, and the inferior constrictor muscles relax so that the esophagus opens

3. superior constrictor muscles contract and initiate a peristaltic wave that forces food into esophagus

4. a peristaltic wave moves food through the esophagus to the stomach

What are the 4 steps of swallowing?

esophagus

contains mucous glands in submucosa, which moisten and lubricate lining of inner wall with mucus and facilitates the passage of food to the stomach.

superior 1/3 is skeletal muscle; middle 1/3 is skeletal+smooth muscle; inferior 1/3 is smooth muscle

Which 1/3rd of esophagus is what kind of muscle?

lower esophageal sphincter

regulates foo passage into stomach, and closes to prevent regurgitation of food

stomach

1L of capacity, limited absorption, 4 different regions

cardia, fundus, body, pylorus

what are the 4 regions of stomach?

cardia

region near opening to esophagus, contains lower esophageal sphincter

fundus

rounded area that rises above cardia; temporary food storage, which sometimes contains swallowed air

body

main portion of stomach; lies b/t fundus and pylorus

pylorus

distal portion of stomach, closest to small intestine; funnel-shaped pyloric antrum narrows to become pyloric canal

Pyloric Sphincter

A smooth muscle that regulates food passage from the stomach to the small intestine.

mucous cells, chief cells, parietal cells, enteroendocrine cells (all produce a mixture called gastric juice)

What are the 4 types of secretory cells that gastric glands contain?

protects stomach’s inner surface from HCl and enzymes

what is mucus’ function in the gastric juice?

pepsinogen

chief cells of the gastric glands

pepsin

formed from pepsinogen in the presence of hydrochloric acid; digests nearly all types of dietary protein into polypeptides

Hydrochloric acid

parietal cells of gastric glands; provides acid environment needed for production and action of pepsin

chemical messengers

enteroendocrine cells in gastric juice to regulate digestive motility and secretion

intrinsic factor

parietal cells of gastric glands that are necessary for vitamin B12 absorption in the small intestine

somatostatin, gastrin, cholecystokinin (CCK)

What are the 3 hormones released to regulate digestion?

cephalic phase

brain controls stomach; 25% - 50% of secretions; sight, taste, smell, or thought of food

gastric phase

stomach controls stomach; 40%-50% of secretions; food in stomach chemically/mechanically stimulates release of gastrin

intestinal phase

intestines control stomach; as food enters intestines, it briefly promotes the secretion of gastric juice from stomach wall

some water, certain salts, certain lipid-soluble drugs, some alcohol

Although the stomach wall is not well-adapted to absorb digestive products, what substances does it absorb? (4)

chyme

food + gastric juices

1. duodenum fills with chyme

2. sensory stretch receptors are stimulated

3. sensory impulses conducted to central nervous system

4. a reduction in parasympathetic activity decreases peristalsis in stomach walls

What are the steps of the enterogastric reflex?