Lecture 17

Question 1

Role of the Respiratory Center:

Answer 1

Respiration controlled by neurons in pons & medulla

Question 2

3 groups of neurons

Answer 2

medullary rhythmicity
pneumotaxic
apneustic centers

Question 3

Medullary Rhythmicity Area:

Answer 3

Controls basic rhythm of respiration

Inspiration for 2 seconds, expiration for 3

Question 4

Autorhythmic cells active for

Answer 4

2 seconds then inactive

Question 5

Expiratory neurons:

Answer 5

inactive during most quiet breathing only active during high ventilation rates

Question 6

Pneumotaxic Area

Answer 6

constant inhibitory impulses to inspiratory area

Question 7

Apneustic Area

Answer 7

stimulatory signals to inspiratory area to prolong inspiration

Question 8

Regulation of Respiratory Center: Cortical Influences

Answer 8

• voluntarily alter breathing patterns
• limitations are buildup of CO2 & H+ in blood
• inspiratory center is stimulated by increase in either

Question 9

Central chemoreceptors in medulla:

Answer 9

• respond to changes in H+ or pCO2

- hypercapnia = slight increase in pCO2 is noticed

Question 10

Peripheral chemoreceptors:

Answer 10

• respond to changes in H+ , pO2 or PCO2
• aortic body—in wall of aorta
• carotid bodies–in walls of common carotid arteries

Question 11

hypoxia =

Answer 11

deficiency of O2

Question 12

hypoxic hypoxia–

Answer 12

low pO2 in arterial blood

Question 13

anemic hypoxia–

Answer 13

too little functioning Hb

Question 14

ischemic hypoxia–

Answer 14

blood flow is too low

Question 15

histotoxic hypoxia–

Answer 15

cyanide poisoning

Question 16

Quick breathing rate response to exercise:

Answer 16

input from proprioceptors

Question 17

Inflation Reflex (Hering-Breurer reflex):

Answer 17

big deep breath stretching receptors produces urge to exhale

Question 18

Factors increasing breathing rate:

Answer 18

emotional anxiety, temperature increase or drop in blood pressure

Question 19

Apnea or cessation of breathing:

Answer 19

by sudden plunge into cold water, sudden pain, irritation of airway

Question 20

Smoker is easily “winded” with moderate exercise:

Answer 20

1. nicotine constricts terminal bronchioles
2. carbon monoxide in smoke binds to hemoglobin
3. irritants in smoke cause excess mucus secretion
4. irritants inhibit movements of cilia
5. in time destroys elastic fibers in lungs & leads to emphysema

Question 21

Asthma:

Answer 21

is an inflammatory disorder of the airways, which causes attacks of wheezing, shortness of breath, chest tightness

Question 22

Influenza:

Answer 22

viral infection that affects mainly the nose, throat, bronchi and, occasionally, lungs. High fever, aching muscles, headache and severe malaise, non-productive cough, sore throat and rhinitis

Question 23

GI tract:

Answer 23

mouth
pharynx and esophagus
stomach
small and large intestine
rectum and anus

Question 24

Mouth function:

Answer 24

bite, chew, swallow

Question 25

function of Pharynx and esophagus—-

Answer 25

transport

Question 26

function of Stomach—-

Answer 26

mechanical disruption; absorption of water & alcohol

Question 27

function of Small intestine–

Answer 27

chemical & mechanical digestion & absorption

Question 28

function of Large intestine—-

Answer 28

absorb electrolytes & vitamins (B and K)

Question 29

function of rectum and anus

Answer 29

defecation

Question 30

Layers of the GI Tract:

Answer 30

1. Mucosal layer
2. Submucosal layer
3. Muscularis layer
4. Serosa layer

Question 31

Mucosa:

Answer 31

1. Epithelium
2. Lamina propria
3. muscularis mucosae

Question 32

Epithelium:

Answer 32

stratified squamous(in mouth,esophagus & anus) = tough 
simple columnar in the rest

Question 33

Lamina propria:

Answer 33

• thin layer of loose connective tissue

- contains BV and lymphatic tissue

Question 34

Muscularis mucosae—

Answer 34

• thin layer of smooth muscle
• causes folds to form in mucosal layer
• increases local movements increasing absorption with exposure to “new” nutrients

Question 35

Submucosa:

Answer 35

-Loose connective tissue:
containing BV, glands and lymphatic tissue
-Meissner’s plexus—

Question 36

Meissner’s plexus—

Answer 36

parasympathetic

innervation

Question 37

Skeletal muscle =

Answer 37

voluntary control
in mouth, pharynx , upper esophagus and anus
control over swallowing and defecation

Question 38

Smooth muscle =

Answer 38

involuntary control
inner circular fibers & outer longitudinal fibers
mixes, crushes & propels food along by peristalsis

Question 39

Auerbach’s plexus (myenteric)–

Answer 39

both parasympathetic & sympathetic innervation of circular and longitudinal smooth muscle layers

Question 40

Serosa:

Answer 40

• An example of a serous membrane
• Covers all organs and walls of cavities
• Secretes slippery fluid
• Consists of connective tissue covered with simple squamous epithelium

Question 41

Peritoneum:

Answer 41

• visceral layer covers organs

- parietal layer lines the walls of body cavity

Question 42

Peritoneal cavity:

Answer 42

potential space containing a bit of serous fluid

Question 43

Parts of the Peritoneum:

Answer 43

Mesentery
Mesocolon
Lesser omentum
Greater omentum

Question 44

Peritonitis =

Answer 44

inflammation
trauma 
rupture of GI tract
appendicitis
perforated ulcer