A&P Chpt 24 Digestive system

The muscularis of the stomach consists of _____ layers; however, the muscularis of the majority of the digestive tract consists of _____ layers

3, 2

Identify the features of the small intestine that function to increase surface area and thus enhance digestion and absorption. Select all that apply. Circular folds Microvilli Villi Lacteals Duodenal papilla

Circular folds Microvilli Villi

Identify the structures that are involved in deglutition (swallowing)

Esophagus Oropharynx Tongue

the aqueous pancreatic juice contains

HCO3- (bicarbonate)

What is the function of HCO3- when it is secreted by the large intestine?

It increases the pH of the feces, which are acidic because of bacterial secretions.

Identify the structures of the digestive tract that are lined with simple columnar epithelium.

Large intestine Stomach Small intestine

Which region of the stomach connects to the small intestine?

Pyloric canal

What is the primary function of the stomach?

Storage and mixing chamber

While anesthetized patients sometimes vomit. Given that the anesthetic eliminates the swallowing reflex, explain why it is dangerous for an anesthetized patient to vomit.

With the loss of the swallowing reflex, the vocal folds no longer occlude the glottis. Consequently, vomit can enter the larynx and block the respiratory tract.

Which of these lipoprotein molecules transports excess lipids from cells back to the liver? a. HDL b. LDL c. VLDL

a. HDL

The majority of ion absorption occurs as a result of _____.

active transport

which of these hormones stimulates stomach secretions? a. cholecystokinin b. insulin c. gastrin d. secretin

c. gastrin

A hexagon-shaped tissue with a portal triad at each corner

hepatic lobule

Identify the strong and infrequent peristaltic contractions that move contents longer distances within the large intestine.

mass movements

Identify the 4 muscles of mastication:

masseter, temporalis, lateral pterygoid, medial pterygoid

The esophagus is in the ______. pharynx upper abdominal cavity mediastinum

mediastinum

Consists of an epithelial lining, a layer of connective tissue referred to as lamina propria and a thin layer of muscle

mucosa

Which layer of the digestive tract is in direct contact with the food consumed? a. mucosa b. muscularis c. serosa d. submucosa

mucosa

Throughout most of the digestive tract, this tunic consists of two layers of smooth muscle: an inner circular layer, and an outer longitudinal layer

muscularis

Acetylcholine, norepinephrine and serotonin are ______ that affect digestive tract ______.

neurotransmitters, motility

The muscle that forms the majority of the lips is the and the muscle that forms the majority of the cheeks is the

orbicularis oris buccinator

The 3 large paired salivary glands are the

parotid sublingual submandibular

Consists of a thin layer of connective tissue and simple squamous epithelium

serosa

True or False: Water absorption in the small intestine occurs as a result of osmosis.

true

The oral cavity is divided into two regions: the _____, which is the space between the lips or the cheeks and the teeth and the ______, which lies medial to the teeth.

vestibule, oral cavity proper

What are the six functions of the digestive system?

1. ingestion and mastication 2. propulsion and mixing 3. secretion 4. digestion 5. absorption 6. elimination

What are the 4 layers of the digestive tract? (listed from inner to outer)

1. mucosa 2. submucosa 3. muscularis externa 4. serosa or adventitia

What are the three major glands associated with the digestive tract?

1. unicellular mucous glands in the mucosa 2. multicellular glands in the mucosa and submucosa 3. multicellular glands (accessory glands) outside the digestive tract.

Select the mechanisms that regulate the digestive system. Select all that apply. A. Nervous mechanisms B. Chemical signals C. Blood hydrogen ion concentrations D. Plasma oxygen concentrations

A. Nervous mechanisms B. Chemical signals

During swallowing, the A) the movement of food results primarily from gravity B) the swallowing center in the medulla oblongata is activated C) food is pushed into the oropharynx during the pharyngeal phase D) the soft palate closes off the opening into the larynx

B) the swallowing center in the medulla oblongata is activated

What muscle type makes up most of the muscularis of the gastrointestinal tract? a. Cardiac b. Smooth c. Skeletal

B. smooth

Identify the components of pancreatic juice. Select all that apply. Hydrochloric acid Bile Bicarbonate ions Enzymes to digest lipids Enzymes to digest nucleic acids Enzymes to digest carbohydrates Enzymes to digest proteins

Bicarbonate ions Enzymes to digest lipids Enzymes to digest nucleic acids Enzymes to digest carbohydrates Enzymes to digest proteins

Identify the structures of the digestive tract that are lined with stratified squamous epithelium. Select all that apply. Esophagus Stomach Anal canal Oropharynx Small intestine Mouth

Esophagus Anal canal Oropharynx Mouth

True or false: Most of the nervous control of the digestive system is through the parasympathetic nervous system.

FALSE Reason: Most nervous control of the digestive system is local, resulting from reflexes within the enteric nervous system.

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

False Reason: It has two layers of smooth muscle.

Discuss why the most effective oral rehydration therapy is water containing sodium and glucose instead of water alone or water and fructose.

Oral rehydration therapy relies on the principle of osmosis. Water follows solutes as they are absorbed across the intestinal epithelium. The combination of sodium and glucose is optimal, since the two moleculs are co-transported by a symporter that is driven by a sodium gradient established by the Na+---K+ pump. hence the present of the sodium aids glucose absorption. Fructose is absorbed by a facilitated diffusion transporter that is not coupled to a sodium gradient.

Identify the parts of the pharynx that function in digestion

Oropharynx Laryngopharynx

Identify the organ that consists of a head located within the curvature of the duodenum and a tail that extends to the spleen

Pancreas

Identify the types of movements that occur within the small intestine.

Segmental contractions Peristaltic contractions

Name the outermost or most superficial layer of the organs in the digestive tract.

Serosa Adventitia

Identify the functions of the liver. Select all that apply. Production of digestive enzymes Synthesis of new molecules Interconversion of nutrients Phagocytosis Production of bile Storage of glycogen, lipids, vitamins and minerals

Synthesis of new molecules Interconversion of nutrients Phagocytosis Production of bile Storage of glycogen, lipids, vitamins and minerals

A patient has a spinal cord injury at level L2. How does this injury affect the patients ability to defecate? What components of the defecation response are still present, and which are lost?

The patient is still able to defecate. Following a meal, the gastrocolic and duodenocolic reflexes initiate mass movement of the feces into the rectum. In the rectum, local reflexes and the defectation reflex cause defecation. However the patient loses awareness of the need to defecate and the ability to prevent defecation voluntarily via the external anal sphincter.

Why doesn't the stomach digest itself?

The stomach wall is protected by large amounts of mucus.

the stomach a. has large folds in the submucosa and mucosa call rugae b. has two layers of smooth muscle in the muscularis tunic c. opening from the esophagus is the pyloric opening d. has an area closest to the duodenum called the fundus e. all of these are correct

a. has large folds in the submucosa and mucosa call rugae

Which cells in the small intestine have digestive enzymes attached to their surfaces?

absorptive cells

The two major divisions of the digestive system include the digestive tract and the organs.

accessory

If the thoracic duct were tied off, which of these classes of nutrients would not enter the circulatory system at their normal rate? a. amino acids b. glucose c. lipids d. fructose e. nucleotides

c. lipids

The proximal end of the large intestine is characterized by a pouch-like structure called the

cecum

The large intestine consists of the _____, and the anal canal.

cecum, colon, rectum

The taste, smell, or thought of food stimulates gastric secretions by activating the ______ phase of gastric regulation.

cephalic

The submucosa consists of ______ tissue.

connective

the hepatic sinusoids a. receive blood from the hepatic artery b. received blood from the hepatic portal vein c. empty into the central veins d. all the above

d. all the above

The ENS if found in a. the submucosa layer b. the muscularis layer c. the serosa layer d. both a and b c. all are correct

d. submucosa and muscularis

The three sections of the small intestine, listed in order as food passes through, are the , the , and then the

duodenum, jejunum, ileum

which of these structures increase the mucosal surface of the small intestine? a. circular folds b. villi c. microvilli d. length of the small intestine e. all of these are correct

e. all of these are correct

which of the following might occur if a person suffers from a severe case of hepatitis that impairs liver function? a. lipid digestion is difficult b. by-products of hemoglobin breakdown accumulate in the blood c. plasma proteins decrease in concentration d. toxins in the blood increase e. all of these occur

e. all of these occur

Bile

emulsifies lipids contains breakdown products from hemoglobin

During stomach filling the rugae _______.

flatten and allow the stomach to increase in volume

The innermost tunic, the mucosa consists of what 3 layers?

inner mucous epithelium lamina propria muscularis mucosae

Micelles are

lipids surrounded by bile salts

Identify the largest internal organ of the body.

liver

Dentin

makes up most of the structure of the teeth

Trypsin, chymotrypsin, and pepsin all aid in the chemical digestion of ______.

proteins

Secretin, cholecystokinin, and peptidases are secretions of the ______.

small intestine

Cholecystokinin, secretin and the vagus nerve all ______ the release of pancreatic juices.

stimulate

Gallbladder function

stores bile

Consists of a thick layer of connective tissue containing nerves, blood vessels, lymphatics and glands

submucosa

The layer of the digestive tract that is a thick layer of connective tissue containing nerves, blood vessels, lymphatics and glands is the _____

submucosa

Identify the functions of mucus secretion in the large intestine. Select all that apply.

Helps fecal matter stick together Lubricates colon wall Protects intestinal lining

Which of these stomach cell types is not correctly matched with its function? a. surface mucous cells---produce mucus b. parietal cells---produce hydrocholoric acid c. chief cells---produce intrinsic factor d. endocrine cells---produce regulatory hormones

c. chief cells---produce intrinsic factor

Victor experienced the pain of a duodenal ulcer during final examination week. Explain what habits caused the ulcer, and recommend possible remedies

even though ulcers are usually caused by bacteria, overproduction of hydrochloric acid due to stress is a possible contributing factor. Reducing hydrochloric acid production is recommended. In addition to antibiotic therapy, commonly recommended treatments include relation, drugs that reduce stomach acid secretion nd antacids to neutralized the hydrochloric acid. Smaller meals are also advised b/c distension of the stomach simulates acid production. in addition, proper diet is important patients are advised to avoid, alcohol, caffeine and a large amounts of protein b/c they simulate acid production. Stress also stimulates the sympathetic nervous system, which inhibits duodenal gland secretion. As a result, the duodenum h less mucous coating, making it more susceptible to gastric acid and enzymes. Relaxing after a meal helps decrease sympathetic activities and increase parasympathetic activities