A&P Exam 4

What are the four stages of respiration?

Pulmonary ventilation

External respiration

Gas transport

Internal respiration

Pulmonary ventilation:

air in/out of lungs

External respiration:

moving 02 to the blood and blood moves CO2 to the air

Gas transport:

CO2 and 02 through the blood, carried with hemoglobin

Internal respiration:

blood moves 02 to the cells and cells move CO2 to the blood

Where does the respiratory zone begin?

At the terminal bronchioles

What are the two layers of the serous membrane?

Visceral layer and the parietal layer

What is intrapulmonary pressure?

Pressure of air inside lungs. Change with muscle contraction & relaxations

What is atmospheric pressure?

Pressure of air outside the body

What is respiratory pressure? How is it calculated? Why is this value important?

Respiratory pressure = intrapulmonary pressure - atmospheric pressure

Explain how volume and pressure are related in the lungs and how they dictate air flow in and out of the lungs:

Increased lung volume decreases internal pressure (drawing air in) and decreased volume increase pressure (forcing air out)

What is the volume of air moved in and out of the lungs during quiet respiration called?

Tidal volume

Inspiratory reserve volume (IRV):

Additional amount of air that can be initiated past a normal breath

Expiratory reserve volume (ERV):

amount of air that can be forcefully exhaled from the lungs after a normal breath out

Residual volume (RV):

amount of air remaining in the lungs after maximal exhalation

Tidal volume (TV):

volume of air in and out at base line - normal breaths

Vital capacity (VC):

how much air you can possibly move in and out

Total lung capacity (TLC):

vital capacity + RV

Forces Vital Capacity:

• Amount of air forcefully expelled following full inhale.

• Measures the total capacity to hold and release air

• detects pulmonary fibrosis, interstitial lung disease

Forced Expiratory Volume:

• Amount of air forcefully expelled during a set amount of time

• Measures the maximum amount of air that can be forced out of the lungs

• Detects asthma, COPD/emphysema

What is the role of smooth muscle in the airways?

Regulates airway diameter and tone

Explain how contraction and relaxation of airway smooth muscle will affect bronchiole diameter, resistance, and air flow:

Smooth muscle contraction reduces bronchiole diameter, causes increased airway resistance and reduced airflow

Why do we have lymphatics in the lungs?

• For maintaining fluid balance

• Clearing excess fluid to prevent pulmonary edema

• Supporting immune defense by transporting immune cells and removing foreign particles

What is the respiratory membrane?

Interface between air and blood

What causes surface tension?

The cohesive, inward pulling forces of hydrogen bonds between water molecules at an air-water interface

How would surface tension affect an alveolus if it were simply lines with a layer of water?

High surface tension would cause the sac to collapse, making re-inflation extremely difficult

What is surfactant and how does it disrupt the effects of surface tension on alveoli?

Reduces surface tension. Prevents water from being able to collapse alveolus

How does Henrys Law apply to respiration?

Gas will dissolve into a liquid in proportion to its partial pressure.

Higher pressure difference = more and faster into solution

Is oxidation going to occur quickly or slowly? What factors might affect heart rate at which blood is oxygenated?

• Blood oxygenation occurs quickly

• Lung health, heart rate, and altitude can affect the speed at which your blood oxygenates

Where does oxygen bind?

02 binds easily in the lungs

Where does carbon dioxide bind?

CO2 binds to globin

What are oxyhemoglobin?

heme bound to oxygen

What are deoxyhemoglobin?

heme with no oxygen

What is affinity?

How much oxygen can bind

Why do we need hemoglobin to transport oxygen in the blood?

Hemoglobin is necessary because oxygen does not dissolve well in water or blood

How much oxygen is dissolved in the blood?

95-100%

How much is oxygen is carried on hemoglobin?

98.5%

Why are locally acidic conditions beneficial for tissues?

It enhances oxygen release and can help with wound repair

Order the organs that will carry food and its various digested forms from mouth to anus:

Mouth → Pharynx → Esophagus → Stomach → Small intestine → Large Intestine → Rectum → Anus

Name the accessory organs:

Teeth, tongue, salivary glands, liver, gallbladder, pancreas

Peristalsis:

Contraction and relaxation of longitudinal and circular muscles that moves contents along the GI tract. Lower gastroesophageal sphincter opens, food into stomach

Segmentation:

Localized, rhythmic contraction of circular muscles that separated and mixed chyme to increase nutrient absorption

What is the peritoneum?

The largest serous membrane in the body, forming a continuous thin, and slick sac that lines the abdominopelvic cavity and covers most abdominal organs

What is a mesentery?

A continuous fan-shaped fold of membranous tissue in the abdomen that attaches the intestines to the posterior abdominal wall

What is the mesentery important?

Acts as a support structure for the digestive organs, containing blood vessels, lymphatics, nerves, and fat, and is increasingly recognized as a distinct organ

In what cavity of the body are the digestive organs largely found?

The abdominal pelvic cavity

Mucosa:

• Epithelial

• Lines mouth to anus

• Secretion absorption and protection

• Lamina propria and Muscularis propria

Submucosa:

• CT

• Contains: capillaries, sensory nerve fibers, lymph vessels, and tons of elastic fibers

Muscularis Externa:

• 2 smooth muscle layers (stomach 3)

• Propulsion and mixture

Serosa:

• Some immune cells

• CT and epithelium

Why does the GI use reflex arcs?

To manage digestion rapidly and efficiently without needing brain input.

• Long coordinates distant parts of the GI tract

• Short is local regulating movement and secretion in real time

What type of epithelium makes up the mucosa?

Stratisfied squamous epithelium

What is the predominant muscle type in the mouth?

Skeletal muscle

What is saliva?

97-99.5% water, slightly acidic, and metabolic waste

What are two antimicrobial compounds?

Amylase and Lipase

Amylase:

Carbohydrates

Lipase:

lipids/fatty acids

What is Deglutition?

Swallowing

Buccal phase:

• Voluntary

• Tongue presses hard palate, swallow

Pharyngeal-esophageal phase:

• Involuntary

• Initiated by bolus transfer

• Nasopharynx closes off

• Epiglottis blocks trachea

Pharynx:

• Area of shared passage for air and food

• Nasopharynx, orophraynx, laryngopharynx

Bolus:

One swallow

What epithelial type makes the lining of the esophagus?

Stratified squamous

What do the esophageal glands in the submucosa do?

Secrete mucus, and epidermal growth factors into the lumen to protect against stomach acid, lubricate the passage of food and aid in mucosal repair

Describe the organization of the muscularis externa:

INNERMOST:

• oblique

• circular

• longitudinal

OUTERMOST

Does the esophagus allow for digestion and/or absorption?

Neither, just propulsion

What are the main functions of the stomach?

• Reservoir for food

• Propulsion

• Mechanical breakdown

• Chemical digestion

• Appetite control (hormones)

• Some absorption

What is the fundus important for?

Indicates that you are hungry or full

What is the pyloric antrum and why is it important?

Highest strength of contraction

What are the rugae and why are they important?

Folds inside stomach that help to stretch the stomach

What are the two mesenteries that attach to the stomach?

Lesser omentus and greater omentum

Lesser Omentus:

Attaches the lesser curvature of the stomach to the liver

Greater Omentum:

attaches the greater curvature of the stomach and hangs down over the intestines

What are the gastric pits?

produce gastric juice (acid and enzymes)

Mucus Neck Cells:

Produce a thin, slightly acidic mucus that differs from surface

Parietal Cells:

produce hydrochloric acid (HCl) and intrinsic factor

Chief cells:

produce and secrete pepsinogen and gastric lipase

Enteroendocrine cells:

Produce hormones found in the gut epithelium that function as key sensors of nutrients and microbial metabolites

Why are parietal cells particularly well suited to secretion?

They have microvilli which increase surface area and make HCl and intrinsic factor

How is the stomach protected from self-digestion?

Through a mucosal barrier

Is denaturing the same digestion?

No

What is denatured from the stomach and how?

Primarily proteins and fats.

• Add HCl to make the protein non functional and safe to eat

What is digested in the stomach and how?

Primarily proteins and fats

• By mixing hydrochloric acid and enzymes to form a semi-liquid mixture called chyme

How are digestion and denaturing linked?

They follow steps in breaking down proteins for nutrient absorption

Every contraction push ______mL of chime into small intestine

~30

The SI returns ___ mL

~27

_____mL into SI per contraction

3

What regulates gastric juice production?

Neural (vagus nerve), hormonal (gastrin), and paracrine (histamine, somatostatin) pathways

What are the three phases of gastric juice production?

1. Cephalic

2. Gastrin

3. Intestinal