EXAM III

Question 1

What is the most important opsonin? Why?

Answer 1

C3b

Has the highest binding affinity

Question 2

Primary or secondary lymph follicles/nodules contain a germinal center? What does this germinal center consist of?

Answer 2

Secondary

B lymphocytes memory B cells, plasma cells, dendritic reticular cells

Question 3

What is the difference between lymph nodules and lymph nodes?

Answer 3

Nodules are apart of lymph nodes and other lymphatic vessels/organs (primary & seconday)

Lymph nodes are enclosed by a capsule

Question 4

What are the primary and secondary lymphoid organs?

Answer 4

Primary - bone marrow and thymus (precursor cells mature into immunocompetent cells programmed to recognize a specific Ag)

Seconday - spleen, tonsils, lymph nodes (trapped Ag stimulate clonal expansions of mature T and B cells)

Question 5

Distinguish between primary and secondary lymph nodules

Answer 5

Primary follicles - virgin B cells and dendritic reticular cells that haven’t been exposed to Ag

Secondary - been exposed to foreign Ag; not present at birth

Question 6

What are the 3 propria-associated lymphoid tissues?

Answer 6

MALT

BALT (bronchial)

GALT

Question 7

Which T cells does MHC I and MHC II express their Ag peptide fragment to?

Answer 7

MHC I = CD8+

MHC II = CD4+ helper

Question 8

What are CD16/56+ T cells? What are they activated by and what do they release?

Answer 8

NK cells

Activated by tumor cells Ags and release cytokines

Question 9

What are HEVs? Where are they found? Whats it used for

Answer 9

High Endothelial Vessels are found in the deep cortex of lymph which allows entry point for circulating differentiated lymphocytes to leave the bone marrow and enter lymph node by easily leaving the venules

Question 10

Define Hassall’s corpuscle. What do they produce and stimulate?

Answer 10

Whorls of highly keratinized medullary epithelial cells in the medulla of the lobules of the thymus

Produce cytokine thymic stromal lymphopoietin

Stimulates thymic dendritic cells needed for single (+) T cell maturation

Question 11

Describe characteristics of the red pulp of the spleen. Function? What does it surround? Explain Billroth cords

Answer 11

Surrounds white pulp

Filters blood

Contains Billroth cords which form red pulp parenchyma = blood cells, plasma cells, APCs

Terminal capillaries open directly into the substance of cords = open circulation

Question 12

What type of epithelium is the respiratory epithelium?

Answer 12

Pseudostratified ciliated columnar epithelium

Question 13

What part of the kidney is the most important in generating the countercurrent osmol gradient?

Answer 13

Loop of Henle

Question 14

What type of epithelium is located within the olfactory?

Answer 14

Pseudostratified columnar without goblet cells, without basement membrane

Question 15

What are the specialized cell types of the pulmonary system? (

Answer 15

Type I Alveolar/Pneumocytes - covers large surface area

Type II Alveolar/Penumocytes - secrete surfactant, contains lamellar bodies w/ lecithin, phagocytize old surfactant (combine w/ proteins from Clara cells)

Clara Cells - secrete surfactant preventing collapse of terminal bronchioles during exhalation

Dust Cells

Question 16

Characteristics of clara cells? Location? Function?

Answer 16

Found only in bronchioles

Secrete surfactant preventing collapse of terminal bronchioles during exhalation

Question 17

Define Type I alveolar cells/Type I Pneumocytes, where are they located?

Answer 17

Less numerous than Type II

Cover largest suface area (more thinner)

Walls of Alveoli

Question 18

Define Type II Alveolar Cells/Pneumocytes

Answer 18

Produce surfactant

Cuboidal/rounded

Stem cells for Type I and Type II

Question 19

What two cells secrete surfactant?

Answer 19

Clara and Type II Alveolar/Pneumocytes

Question 20

Characteristics of Type II Alveolar cells

Answer 20

​Lamellar bodies​ = Distinctive under EM; contain lecithin

Phagocytize old surfactant; more round

Can divide and replace Type I

Secreted from apical domain of cells

Combine w/ proteins from Clara cells

Produce phospholipid-protein surfactant that coats alveolar walls

Question 21

Define Clara cells, where are they found, which cell do they work with in the pulmonary system?

Answer 21

Secrete surfactant & lipoprotein that prevents collapse of terminal bronchioles during exhalation

Bronchioles

Identified by apical surface that bulges into lumen of airway

Abundant SER; greater # with less ciliated columnar cells

Work with Type II Pneumocytes

Question 22

What are dust cells and what are their roles? Where are they located?

Answer 22

Macrophages; derived from monocytes

Phagocytize pollutants, bacteria, surfactant

Walls of alveoli

Question 23

Where are intercalated cells found? What is their function in terms of ion concentration and its relationship with angiotensin-aldosterone pathway?

Answer 23

Late DCT and Collecting Tubule

Reabsorb K+ during depletion, secrete H+ or Bicarbonate

Affected by angiotensin (increases Na+ reabsorption)

Question 24

What are the types of T cells involved during T cell differentiation?

Answer 24

Double (-) T cells - lack cell surface molecules, enter cortex from blood vessels, proliferate in subscapular area

Double (+) T cells - move to outer cortex, express CD4 & CD8 & TCR, interact w/ epithelial cells w/ MHC I & II for clonal selection,

Single (+) T cells - move to inner cortex, express TCR and EITHER CD4 or CD8

Medulla = clonal deletion completed (copies of T cells)

Question 25

List the layers of the epidermis from deep to outermost Thick Skin vs Thin Skin

Answer 25

Thick: **R**emember, **P**lease **B**ring **S**ome **G**ood **C**hapstick Thin: **R**emember, **P**lease **B**ring **S**ome **G**ood **L**ip **C**hap Stratum **basale/germinativum** Stratum **spinosum** Stratum **granulosum** Stratum **lucidum** - absent in thin skin Stratum **corneum**

Question 26

What are the steps necessary during differentiation of T cells? (4)

Answer 26

Double negative Double positive Single positive Clonal deletion

Question 27

What are the characteristics of double negative T cells? Where are they located?

Answer 27

Lack cell surface molecules (in mature T cells) Proliferate in subcapsular area (outside cortex) **Enter cortex from blood vessels**

Question 28

What are the characteristics of double positive T cells and what do they express?

Answer 28

Express **both CD4 & CD8 coreceptors and TCR receptors** Are deeper in cortex Confronted with epithelial cells w/ cell surface MHC classes I and II for clonal selection

Question 29

What do single positive T cells express?

Answer 29

**Either CD4 or CD8 and TCR receptors** **Mature T cells**

Question 30

Where does clonal deletion of T cells occur?

Answer 30

Medulla

Question 31

What occurs in the white pulp of the spleen?

Answer 31

Clonal expansion of Ag-stimulated lymphocytes

Question 32

What is the function of the marginal zone of the spleen?

Answer 32

Forms sinusoidal interface between red pulp and white pulp The site of **initial Ag exposure** to lymphocytes

Question 33

What are the 4 arteries of the spleen?

Answer 33

**Splenic artery** - enters hilus **Trabecular artery** - branches off **Central artery** - where adventitia loosens and becomes mesh-like reticulum infiltrated with lymphocytes. **A penicillus is formed when capillaries enter red pulp** **Penicullar arterioles --\> Terminal Capillaries** Veins: Venous Sinuses, Pulp Vein, Trabecular Vein, Splenic veins, Hilus

Question 34

What are Meissner's Corpuscle? What is their function?

Answer 34

(Tactile corpuscle) Type of mechanoreceptor Type of nerve ending in the skin responsible for sensitivity to light touch

Question 35

What are Pacini Corpuscles

Answer 35

One of the 4 major types of mechanoreceptors Nerve endings in skin responsible for sensitivity to vibration and pressure

Question 36

Where are intercalated cells found? What is their function in terms of ion concentration and its relationship with angiotensin-aldosterone pathway?

Answer 36

**Late Distal Tubule and Medullary CT** **Reabsorb K+** **Secrete H+ or bicarbonate** Affected by **Angiotensin II**

Question 37

Where are principal cells found? What is their function in terms of ion concentration and its relationship with angiotensin-aldosterone pathway?

Answer 37

**Late DCT and Collecting Duct** **Reabsorb Na+ and Water** **Secrete K+** **Affected by Aldosterone**

Question 38

Define space of Disse and describe its location

Answer 38

**Separates hepatic cells from endothelial cells** (between hepatocytes and sinusoids; separates basolateral domain of the hepatocytes from blood circulating in the hepatic sinusoid ## Footnote **Active in transfer between blood and parenchyma**

Question 39

Function of sinusoids in the liver; explain both hepatic lobules

Answer 39

**Canal area that feeds into the _central venule_ which is within the _Classic lobule_** Portal triads are at an angle (hepatic artery, portal vein, bile duct) **Portal lobules -** contain 3 central venules of adjacent lobules that form a triangle

Question 40

For CCK hormone, state the site of secretion, targets, and effects

Answer 40

**Duodenum** (upper intestinal mucosa) in response to gastric contents **Targets pyloric sphinctor to slow stomach emptying** Stimulates **bile release** **from gall bladder** Stimulates **secretion of pancreatic enzymes** Competitive inhibitor of **gastrins**

Question 41

For gastrin hormone, state the site of secretion, targets, and effects

Answer 41

**Duodenum** Targets **Pancreas** **Insulin release by pancreatic beta cells** **Bicarbonate secretion by pancreas**

Question 42

For secretin hormone, state the site of secretion, targets, and effects

Answer 42

**Pyloric-antral portion of stomach** Targets **stomach** Stimulates **HCl production by gastric parietal cells** **gastric motility** **Insulin release by pancreatic beta cells**

Question 43

Which taste bud is only found on along the sulcus terminalis? Circumvallate papillae Filiform papillae Foliate papillae Fungiform papillae

Answer 43

**Circumvallate papillae**; projections along sulcus terminalis ## Footnote **Along the lateral walls**

Question 44

Which taste bud is found on the oral surface of epithelium of the tongue? Circumvallate papillae Filiform papillae Foliate papillae Fungiform papillae

Answer 44

**Fungiform papillae** mushroom appearance

Question 45

What are the 4 layers of the digestive gut tube?

Answer 45

**Mucosa** **Submucosa** **Muscularis externa** **Serosa & Adventitia**

Question 46

Type of epithelium in the mucosal layer of the digestive gut tube? What are the 2 layers?

Answer 46

**Stratified squamous transitioning to simple columnar** Lamina propria - loose areolar CT Muscularis mucosa - 1-3 layers of smooth muscle

Question 47

Type of epithelium in submucosa of the digestive tube? Is it vascularized? What special item is within it

Answer 47

**Dense, irregular CT** **Vascularized** **Meissner's plexus** (nerve/submucosa plexus)

Question 48

Type of epithelium in the muscularis externa layer of the digestive tube? What are the 2 layers and what special item does it hold

Answer 48

**Inner circular layer of SM** (regulates lumen size) **Outer longitudinal layer** (regulates rhythmic movement of GI tract) **Myenteric/Auerbach's nerve plexus** - between the two muscle layers

Question 49

What type of epithelium or CT is within the Serosa and Adventitia of the digestive gut tube?

Answer 49

Serosa **Dense, irregular CT;** forms visceral peritoneum, covers intraperitoneal portions of abdominal organs Adventitia **Dense, irregular CT with adipose tissue** Covers retroperitoneal portions of digestive system

Question 50

Where does carbohydrate digestion begin?

Answer 50

**Mouth** via amylase

Question 51

Which of the following best describes the olfactory mucosa? Stratified columnar epithelium with goblet cells and a distinct basement membrane Simple ciliated columnar epi with goblet cells and a distinct basement membrane Stratified, non-keratinized epi lacking goblet cells with thick basement membrane Pseudostratified columnar epi lacking goblet cells w/ no distinct basement membrane

Answer 51

Pseudostratified columnar epi lacking goblet cells with no distinct basement membrane

Question 52

Which of the following is NOT a necessary part of the respiratory membrane? Pneumocyte I Basal lamina of pneumocyte I Dust cells Basal lamina of endothelial cell Endothelial cell

Answer 52

Dust cells

Question 53

Which of the following is characteristic of an arteriole? Thick tunica adventitia and large lumen Thick tunica media in relation to size of lumen Thin tunica media and relatively large lumen Large blood-filled lumen Large amounts of elastic fibers in the tunica media

Answer 53

Thick tunica media in relation to size of lumen

Question 54

Where in the body of a normal, healthy individual would you expect most erythrophagocytosis to be occurring? Marginal zone of spleen Hematopoietic cord in bone marrow Cord of Billroth in spleen Paratrabecular sinus in lymph node

Answer 54

Cord of Billroth in spleen

Question 55

Which of the following sequences best describes the flow of red blood cells through the spleen? Trabecular arteries, central arteries, splenic arteries, penicullus, venous sinuses Splenic artery, central arteries, trabecular arteries, venous sinuses, penicillus Splenic artery, central arteries, trabecular arteries, venous sinuses, penicillus Trabecular arteries, splenic arteries, central arteries, penicullus, venous sinuses Splenic artery, trabecular arteries, central arteries, penicullus, venous sinuses

Answer 55

Splenic artery, trabecular arteries, central arteries, penicillus, venous sinuses

Question 56

The simple cuboidal epithelium of this portion of the kidney tubule is composed of cells in the form of truncated pyramids which are characterized by basal striations that mark the location of mitochondria PCT Descending thin segment of LOH Ascending thick segment of LOH DCT Collecting Duct

Answer 56

PCT

Question 57

Renin is secreted by which of the following? Liver Macula densa cells Atrial cells of the heart Mesangial cells Juxtaglomerular cells

Answer 57

Juxtaglomerular cells