LAB TIME/DATE

NAME _

Anatomy of theDigestive System

General Histological Plan of the Alimentary Canal1. The general anatomical features of the alimentary canal are listed below. Fill in the table to complete the information.

Subdivisions of the layerWall layer (if applicable) Major functions

1) epithelium; 2) lamina propria; absorptionmucosa 3) muscularis mucosa secretion

submucosa (not applicable) vascular supply for mucosa; protection

1) circular layer churning; mixing; propulsion offood along the tractmuscularis extern a 2) longitudinal layer

(not applicable) protection and anchoring for adventitia; reduction ofserosa or adventitia friction for abdominal organs by serosa

~ Organs of the Alimentary Canal2. The tubelike digestive system canal that extends from the mouth to the anus is known as the _a_l_im_e_n_ta_ry..:....- _

canal or the gastrointestinal (GJ) tract.

3. How is the muscularis extema of the stomach modified? It has a third (obliquely oriented) muscle layer.

How does this modification relate to the function of the stomach? Vigorous churning activity occurs here.

4. What transition in epithelial type exists at the gastroesophageal junction? Changes from stratified squamous (esophagus) to

simple columnar (stomach)

How do the epithelia of these two organs relate to their specific functions? The esophagus is subjected to constant abrasion

(stratified squamous is well adaptedfor this). The stomach has secretory (and some absorptive)functions and is better protectedfrom acid.

5. Differentiate between the colon and the large intestine. The large intestine includes the colon, but also includes the cecum, ver-

miform appendix, rectum, and anal canal.

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6. Match the items in column B with the descriptive statements in column A.

ColumnA ColumnB

I. structure that suspends the small intestine from the posterior body a. anuswall

y 2. fingerlike extensions of the intestinal mucosa that increase the b. appendix

surface area for absorptionc. circular folds

p 3. large collections of lymphoid tissue found in the submucosa of thesmall intestine d. esophagus

c 4. deep folds of the mucosa and submucosa that extend completely or e. frenulumpartially around the circumference of the small intestine

n v 5. regions that break down foodstuffs mechanically f. greater omentum

w 6. mobile organ that manipulates food in the mouth and initiates hard palateg.swallowing

q 7. conduit for both air and food h. haustra

f k 8. three structures continuous with and repre- 1. ileocecal valvesenting modifications of the peritoneum

d 9. the "gullet"; no digestive/absorptive functionJ. large intestine

s 10. folds of the gastric mucosa k. lesser omentum

h II. sacculations of the large intestine 1. mesenterym 12. projections of the plasma membrane of a mucosal epithelial cell

m. microvilli13. valve at the junction of the small and large intestines

n. oral cavity14. primary region of food and water absorption

e 15. membrane securing the tongue to the floor of the mouth o. parietal peritoneum

j 16. absorbs water and forms feces p. Peyer's patchesx 17. area between the teeth and lips/cheeks

q. pharynxb 18. wormlike sac that outpockets from the cecum

r. pyloric valvev 19. initiates protein digestionk 20. structure attached to the lesser curvature of the stomach s. rugae

2I. organ distal to the stomach t. small intestiner 22. valve controlling food movement from the stomach into the

duodenum u. soft palate

u 23. posterosuperior boundary of the oral cavity v. stomach

24. location of the hepatopancreatic sphincter through which pancre- w. tongueatic secretions and bile pass

0 25. serous lining of the abdominal cavity wall x. vestibule

j 26. principal site for the synthesis of vitamin K by microorganisms y. villia 27. region containing two sphincters through which feces are expelled

from the body z. visceral peritoneum'------'g 28. bone-supported anterosuperior boundary of the oral cavity

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7. Correctly identify all organs depicted in the diagram below.

Oral cavity proper Parotid gland and duct

Sublingual glandand ducts

~----ir---- Pharynx

Submandibulargland and duct

Gallbladder

.~---------------------- -J~ __ Esophagus

Liver----...!.~/~::;;.;....---f-T T Cardiac "gion oj the stomach.

Pyloric portion of the stomachHepatic duct __ ,!%~~!rr,---~'(J(~~~~£:.--

Cystic duct

Common bile ductDuodenum

T-+--------- Splenic flexureI(left colic flexure)

S~~~~~~~~7i~~~t--4!-l-_ Pancreas with duct

Transverse colon

~~~~:;~;nJl~::--T---Rectum

Appendix

Review Sheet 38 261

8. You have studied the histological structure of a number of organs in this laboratory. Three of these are diagrammed below.Identify and correctly label each.

(a) stomach

gastricgland

1.i.4l-+\-l.:..i.f/q:;::::I=-- vill i

(b) ileum (distal small intestine)

Accessory Digestive Organs

~w--laminapropria

-ei!3h-iI--~- villi

'-==~=-i$~ ~•..-="""'::-I intestinal gland

duodenal gland

(c) duodenum (proximalsmall intestine)

9. Correctly label all structures provided with leader lines in the diagram of a molar below. (Note: Some of the terms in the keyfor question 10 may be helpful in this task.)

262 Review Sheet 38

Crown

Neck {

Root

Enamel

Dentin

Pulp cavity

Gingiva

Peridontalligament

Bone

II'W--#--F+- Root canal

Cementum

Bloodvesselsand nervesin pulp

10. Use the key to identify each tooth area described below. Key: a. anatomical crown

_c 1. visible portion of the tooth in situ b. cementum

_b 2. material covering the tooth root c. clinical crown

_e 3. hardest substance in the body d. dentin

_h 4. attaches the tooth to bone and surrounding alveolar structures e. enamel

"",J,--' __ 5. portion of the tooth embedded in bone f. gingiva

_d 6. forms the major portion of tooth structure; similar to bone g. odontoblast

--'g'---- __ 7. produces the dentin h. periodontal ligament

___ 8. site of blood vessels, nerves, and lymphatics i. pulp

_a 9. entire portion of the tooth covered with enamel j. root

11. In the human, the number of deciduous teeth is _2_o__ ; the number of permanent teeth is _3_2 _

. 212312. The dental formula for permanent teeth IS 2: 1:2:3 X 2

Explain what this means. There are 2 incisors, 1 canine, 2 premolars, and 3 molars in each jaw (upper and lowerY/rom the median

-r>; line posteriorly.2,1,0,2

What is the dental formula for the deciduous teeth? 2,1,0,2 X_2 _ 20

13. What teeth are the "wisdom teeth"? _T_h_e_n_u_m_b_e_r_3---,(_m_o_st-,p~o_s_te_r_io_r,-)_m_o_la_r_s. _

14. Various types of glands form a part of the alimentary tube wall or duct their secretions into it. Match the glands listed in col-umn B with the function/locations described in column A.

ColumnA Column B

_a 1. produce(s) mucus; found in the submucosa of the small intestine a. duodenal glands

L 2. produce(s) a product containing amylase that begins starchbreakdown in the mouth

b. gastric glands

c. intestinal crypts_e 3. produce(s) a whole spectrum of enzymes and an alkaline fluid that is

secreted into the duodenum d. liver

_d 4. produce(s) bile that it secretes into the duodenum via the bile duct e. pancreas

_b 5. produce(s) HCI and pepsinogen f. salivary glands

c 6. found in the mucosa of the small intestine; produce(s) intestinal juice

15. Which of the salivary glands produces a secretion that is mainly serous? _P_a_,_'o_ti_d_. _

Review Sheet 38 263

16. What is the role of the gallbladder? To store and concentrate bile made by the liver.

17. Name three structures always found in the portal triad regions of the liver. _B_,_·a_n_ch~of,--th_e_b_il_e_d_u..:..ct _

_ b_,_·a_n_c_h_of"--h--'ep'--a_t_ic_a_r_t_e'-"-y and branch of hepatic portal vein

18. Where would you expect to find the Kupffer cells of the liver? _L_l_·n_in-"g'--t_h_e_s_in_u_so_i_ds_. _

What is their function? Phagocytosis of debris and worn-out blood cells.

19. Why is the liver so dark red in the living animal? _B_ec_a_u_s_e_it_i_s_a_b_l_oo_d_re_s_e_rv_o_il_·. _

20. The pancreas has two major populations of secretory cells-those in the islets and the acinar cells. Which population serves

the digestive process? _A_c_i_na_r_ce_l_ls_. _

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