BIO 114 - CH. 17, 20, & 21

True or False: The carbonic acid ion is joined to a hydrogen ion by the enzyme carbonic anhydrase.

False

True or False: The first step in the formation of hydrochloric acid is the active transport of carbon dioxide into the parietal cells.

False

True or False: The majority of the muscularis externa consists of two layers of skeletal muscle.

False

True or false: Most absorption of digestive products occurs in the stomach.

False

True or false: When chyme enters the duodenum, gastric secretions increase.

False

Collectively, hydrochloric acid, water, pepsin, and mucus all are components of what fluid?

Gastric juice

Which peptide hormone increases the secretory activity of gastric glands and promotes the release of histamine from gastric mucosal cells?

Gastrin

Where is the stomach located?

In the upper left portion of the abdominal cavity

What is the innermost layer of the wall of the digestive tract called?

Mucosa

What enzyme is produced by the stomach?

Pepsin

When hydrogen ions pass from the parietal cell into the duct of the gastric gland, they are exchanged for what ion?

Potassium ion

Papillae

Projections that move food, contain taste buds

Peristalsis

Ring of contraction progresses down tube, propels food particles down the tract in wavelike motion

Which muscle type makes up most of the muscularis of the gastrointestinal tract?

Smooth

Name the J-shaped, pouch-like organ that hangs inferior to the diaphragm in the upper left portion of the abdominal cavity.

Stomach

Mechanical digestion

Breaks down large pieces of food into smaller ones, but does not change chemical composition

In the parietal cells, the enzyme carbonic anhydrase causes a reaction between which two compounds or molecules?

Carbon dioxide and water

The hydrogen ions used to form hydrochloric acid in the stomach are derived from what compound?

Carbonic acid

Lingual frenulum

Connects tongue to floor of mouth

Myenteric plexus

Controls gastrointestinal motility

Submucosal plexus

Controls secretions

Digestion

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

What is the definition of digestion?

The mechanical and chemical breakdown of foods into smaller forms

Tongue

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

True or false: Gastrin functions to increase the production of HCl in the stomach.

True

True or false: The body utilizes the absorbed nutrients to produce ATP.

True

The ion exchange molecule in the plasma membrane of parietal cells exchanges __________ ions going out for __________ ions coming in.

bicarbonate, chloride

The largest segment of the stomach is the ________.

body

Secretions essential to stomach function are regulated in three phases: the _____ phase, the _____ phase, and the ______ phase.

cephalic, gastric, intestinal

The ____________ cells secrete pepsinogen and the ____________ cells secrete hydrochloric acid (HCl). The third cell type secretes mucus. These cells are the ____________ cells.

chief, parietal, mucous

The soupy mixture of semidigested food formed in the stomach is known as __________.

chyme

The mechanical and chemical breakdown of foods into forms that the cells can use is called ______.

digestion

The process of breaking down foods, either mechanically or chemically, into forms that cell membranes can absorb is called _________.

digestion

Indicate which of the following root words means "stomach."

gastr-

Tubular glands that open into gastric pits of the fundus and body of the stomach are called _______ glands.

gastric

n the lining of the stomach are small openings called ______ that lead into tubular structures called ______.

gastric pits; gastric glands

The inner lining of the stomach contains openings of the ducts from the ____________ glands. These glands contain three types of cells, whose secretions together form ____________ juice.

gastric, gastric

A peptide hormone that increases the secretory activity of gastric glands is called _______.

gastrin

Gastric juice secretion is stimulated by ______ impulses from the ______ nerve.

parasympathetic, vagus

This double-layered membrane is located between the ____________ peritoneum that lines the abdominal cavity and the ____________ peritoneum that surrounds the digestive organs.

parietal, visceral

One function of HCl is to remove some amino acids from pepsinogen, converting it to ____________ , an active enzyme.

pepsin

The mesentery is the part of the ____________ that is responsible for connecting portions of the small intestine to the abdominal wall.

peritoneum

Openings at the ends of tubular gastric glands in the gastric mucosa, as indicated by the arrows are called gastric _________.

pits

The mesentery is attached to the ____________ part of the abdominal wall and allows the segments of the intestines to move against one another without friction.

posterior

Both HCl and pepsin function to chemically breakdown and digest ____________ .

proteins

The layer in the wall of the alimentary canal that is rich in blood vessels and lymphatic vessels that carry away absorbed materials is the ________.

submucosa

The layer in the wall of the alimentary canal that is rich in blood vessels and lymphatic vessels that carry away absorbed materials is the __________.

submucosa

The thick layer of connective tissue between the mucosa and the muscularis externa in the wall of the digestive tract is the ______.

submucosa

The forceful ejection of stomach and intestinal contents from the mouth is called ______.

vomiting

When the stomach lining is irritated significantly, sensory signals are sent to the brainstem, and motor signals return to various structures to cause ______.

vomiting

Enteroendocrine cells

-Found in stomach and small intestine -Secrete hormones to regulate GI organs and processes

Teeth

-Hardest structures in the body -Not part of skeletal system -Begin mechanical digestion

Mucosa

-Innermost layer, mucous membrane -Folded in some areas to increase surface area -Absorbs dietary nutrients, secretes mucus and enzymes

What are the three phases of gastric secretion?

-Intestinal phase -Cephalic phase -Gastric phase

Propelling movements

-Moves materials in one direction -Peristalsis

The wall of alimentary canal is composed of 4 layers; from innermost to outermost, the layers are:

-Mucosa -Submucosa -Muscularis (externa) -Serosa

Muscularis (externa)

-Muscle tissue, contains circular and longitudinal layers -Moves tube and food materials

Serosa

-Outermost layer, serous fluid eliminates friction -Visceral peritoneum of organs within abdominal cavity

Which nervous systems innervate the alimentary tract of the digestive system?

-Parasympathetic division of autonomic nervous system -Sympathetic division of autonomic nervous system

List four components of gastric juice. -Pepsin -Bicarbonate -Water -Lipase -Hydrochloric acid -Secretin

-Pepsin -Water -Lipase -Hydrochloric acid

Soft palate

-Posterior position -Consists of muscular arch -Ends in uvula

What is the effect of parasympathetic impulses on gastric secretion?

-Stimulates release of gastric juice -Stimulates the release of gastrin

Mixing movement

-Type of movement in alimentary canal -Muscle in small sections contracts rhythmically -Does not move materials in one direction

Put in correct order the events resulting in the stimulation of the gastric glands. -Gastrin stimulates glands to release more gastric juice. -Impulses conducted by parasympathetic preganglionic nerve fibers (in vagus nerve). -Impulses stimulate the release of gastrin into the bloodstream. -Parasympathetic postganglionic impulses stimulate the release of gastric juice from gastric glands.

1. Impulses conducted by parasympathetic preganglionic nerve fibers (in vagus nerve). 2. Parasympathetic postganglionic impulses stimulate the release of gastric juice from gastric glands. 3. Impulses stimulate the release of gastrin into the bloodstream 4. Gastrin stimulates glands to release more gastric juice.

Complete the following sentences that describe the alimentary canal and its walls. Then place the sentences in order, listing structures/layers from deep to superficial, starting with the small intestinal lumen. -The ____________ contains the surface epithelium that allows for absorption of nutrients, as wells as glands for secretion. -The ____________ is composed mostly of connective tissue, nerves, and vessels, which help to nourish surrounding tissues. -The ____________ is composed of epithelia and connective tissues that reduce friction between organs in the abdominal cavity. -The ____________ is where nutrients and water are mixed with secretions. -The ____________ is responsible for the movement of substances through the alimentary canal.

1. The LUMEN is where nutrients and water are mixed with secretions. 2. The MUCOSA contains the surface epithelium that allows for absorption of nutrients, as wells as glands for secretion. 3. The SUBMUCOSA is composed mostly of connective tissue, nerves, and vessels, which help to nourish surrounding tissues. 4. The MUSCULAR LAYER is responsible for the movement of substances through the alimentary canal. 5. The SEROSA is composed of epithelia and connective tissues that reduce friction between organs in the abdominal cavity.

Which ion is transported into the bloodstream?

Bicarbonate ion

Mastication

Mechanical breakdown of solid particles, mixes them with saliva

The mesentery contains long _____________ that branch to supply the small intestine.

arteries and veins

Lips

-Highly mobile structures that surround the mouth opening -Sensory receptors judge temperature and texture of food -Boundary between skin and mucous membrane inside mouth

How many teeth do humans have?

-20 primary (deciduous) teeth' -32 secondary (permanent) teeth

List the substances absorbed from the stomach. -Alcohol -Small volumes of water -Lipid-soluble drugs -Protein

-Alcohol -Small volumes of water -Lipid-soluble drugs

Hard palate

-Anterior portion -Consists of palatine processes of maxillae and palatine bones

Digestive system

-Carry out mechanical and chemical digestion, as well as ingestion, propulsion, absorption, and defecation -Consists of the alimentary canal and accessory organs

Types of teeth

-Central incisors -Lateral incisors -Canines (cuspids) -First premolars (bicuspids) -First molars -Second molars -Third molars

Submucosa

-Connective tissue layer -Nourishes cells, transports absorbed food molecules

Accessory organs

-Consists of organs that empty secretions into the alimentary canal -Food does not pass through -Salivary glands, liver, gallbladder, pancreas

Mouth

-First part of alimentary canal -Ingests food -Organ of speech -Sensory reception

Alimentary canal

-Food passageway -Consists of organs that extend from the mouth to the anus -Mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anal canal -Muscular tube, about 8m long

Cheeks

-Form the lateral walls of the mouth -Contains muscles for facial expression and chewing -Lined by stratified squamous epithelium

Palate

-Forms the roof of the oral cavity -Consists of hard and soft palates

Complete the sentences and then arrange them into a logical paragraph order to explain protein digestion and absorption. -The act of protein digestion begins in the mouth with ____________ digestion. -The final products are ____________ that are absorbed through the intestinal wall into the ____________ . -Chemical digestion is continued in the small intestine, where enzymes from the ____________ (trypsin, chymotrypsin, and carboxypeptidase) and from the ____________ (peptidase) continue the breakdown of proteins. -Once in the stomach, ____________ digestion begins with the enzyme ____________ , which hydrolyzes peptide bonds.

1. The act of protein digestion begins in the mouth with MECHANICAL digestion. 2. Once in the stomach, CHEMICAL digestion begins with the enzyme PEPSIN, which hydrolyzes peptide bonds. 3. Chemical digestion is continued in the small intestine, where enzymes from the PANCREAS (trypsin, chymotrypsin, and carboxypeptidase) and from the INTESTINE (peptidase) continue the breakdown of proteins. 4. The final products are AMINO ACIDS that are absorbed through the intestinal wall into the BLOODSTREAM.

Using the words provided, complete each sentence describing the digestive process. Then place the sentences in the correct order of occurrence. -Indigestible residues, along with some of the non-reabsorbed secretions of the digestive organs, are moved into the ____________ , where fluids are removed and a remaining solid is created. -The final step requires ____________ , where the fecal matter is excreted from the body. -Breaking down food, first mechanically and then chemically, is referred to as the process of ____________ . -Once food is broken down into chemical monomers, the digestive system works by a means of ____________ to move nutrients from the digestive tract into the cells of the body. -The digestive process begins with the ____________ of food.

1. The digestive process begins with the INGESTION of food. 2. Breaking down food, first mechanically and then chemically, is referred to as the process of DIGESTION 3. Once food is broken down into chemical monomers, the digestive system works by a means of ABSORPTION to move nutrients from the digestive tract into the cells of the body. 4. Indigestible residues, along with some of the non-reabsorbed secretions of the digestive organs, are moved into the LARGE INTESTINE where fluids are removed and a remaining solid is created. 5. The final step requires DEFECATION, where the fecal matter is excreted from the body.

Complete each sentence describing the sphincters located throughout the digestive tract. Then rearrange the sentences in order from proximal to distal through the digestive tract. -The junction of the small and large intestines is the location of the ____________ sphincter, which regulates movement of intestinal contents into the large intestine. -The ____________ sphincter regulates the movement of food from the stomach to the small intestine. -The first sphincter of the digestive system, called the ____________ muscle, surrounds the entrance to the oral cavity. -The ____________ constrictor muscles act as a sphincter, preventing air from entering the esophagus but relaxing to allow food to pass through. -At the terminal end of the esophagus is the ____________ sphincter, which controls the entrance of food into the stomach. -The voluntary relaxation of the ____________ sphincter, which is composed of skeletal muscle, is the final step in defecation. -The involuntarily controlled ____________ sphincter is composed of smooth muscle that relaxes at the onset of defecation.

1. The first sphincter of the digestive system, called the ORBICULARIS ORIS muscle, surrounds the entrance to the oral cavity. 2. The INFERIOR constrictor muscles act as a sphincter, preventing air from entering the esophagus but relaxing to allow food to pass through. 3. At the terminal end of the esophagus is the LOWER ESOPHAGEAL sphincter, which controls the entrance of food into the stomach. 4. The PYLORIC sphincter regulates the movement of food from the stomach to the small intestine. 5. The junction of the small and large intestines is the location of the ILEOCECAL sphincter, which regulates movement of intestinal contents into the large intestine. 6. The involuntarily controlled INTERNAL ANALsphincter is composed of smooth muscle that relaxes at the onset of defecation. 7. The voluntary relaxation of the EXTERNAL ANAL sphincter, which is composed of skeletal muscle, is the final step in defecation.

Complete the sentences and put them in order to describe the process of deglutition (swallowing). -The ____________ closes off the top of the larynx so food does not enter the ____________ . -A reflex then causes the elevation of the ____________ , closing off the nasal cavity. -A type of movement called a ____________ wave pushes the food down the ____________ to the ____________ . -The tongue forms the mass of food into a ____________ . -The tongue then pushes the newly formed mass into the ____________

1. The tongue forms the mass of food into a BOLUS. 2. The tongue then pushes the newly formed mass into the PHARYNX. 3. A reflex then causes the elevation of the SOFT PALATE, closing off the nasal cavity. 4. The EPIGLOTTIS closes off the top of the larynx so food does not enter the TRACHEA. 5. A type of movement called a PERISTALTIC wave pushes the food down the ESOPHAGUS to the STOMACH.

The release of secretin can be stimulated by which of the following? -Hydrochloric acid in chyme -The hormone gastrin -Partially digested carbohydrate -Partially digested protein

Hydrochloric acid in chyme

Parasympathetic impulses

Increase activities of digestive system (secretion and motility)

Sympathetic impulses

Inhibit digestive actions (secretion and motility)

What molecules are absorbed into the lymph?

Long-chain fatty acids

Palatine tonsils

Lymphatic masses on sides of tongue

Lingual tonsils

Lymphatic tissue masses on root of tongue

Pharyngeal tonsils (adenoids)

Masses of lymphatic tissue in posterior wall of pharynx

Incisors

Used for biting

Chemical digestion

Uses enzymes to break down food particles, by changing them into simpler chemicals

Mucus is an ____________ secretion that helps to protect the stomach lining.

alkaline

In the ducts of the gastric glands, __________ ions are actively transported into the ducts in exchange for __________ ions which enter the parietal cells.

hydrogen, potassium

In a tube such as the digestive tract, the hollow internal passageway is called the ________.

lumen

The physical breakdown of food into smaller particles (by processes such as chewing and segmentation) is known as ________ digestion.

mechanical

The motor functions of the alimentary canal are _________ movements that combine food with digestive fluids and __________ movements that move materials along the digestive tract.

mixing, propelling

The alimentary canal consists of four layers that are, beginning with the innermost tissues, the _________, submucosa, muscularis externa, and ___________.

mucosa, serosa