WGU OA D313 Questions with 100% accurate solutions 2026-2027

pulmonary arteries

L and R branches of the pulmonary trunk that carry deoxygenated blood from the heart to each of the lungs

path of blood through the heart

RA via superior and inferior vena cava

RA to RV via tricuspid valve (R AV valve)

RV to pulmonary trunk and arteries via semilunar valve

pulmonary circuit to LA via pulmonary veins

LA to LV via bicuspid valve (mitral valve)

LV to Aorta via aortic valve

Aorta to everywhere except lungs

describe elastic arteries

Close to the heart

thick walls

larger than 10 mm

conducting arteries

describe muscular arteries

far from heart

.1-10 mm

thick tunica media

distributing arteries

describe fenestrated capillaries

Has some endothelial cells that contain pores (fenestrations), more permeable than continuous capillaries, function in absorption or filtrate formation, located in small intestines, endocrine glands, and kidneys

describe sinusoid capillaries

flat, intracellular gaps

incomplete basement

allows passage for large molecules

bone marrow, spleen, liver, adrenal glands

vasomotion

blood passing from arterioles to capillaries to venules by contraction and relaxation of precapillary sphincters

bulk flow

The movement of a fluid due to a difference in pressure between two locations.

active transport

the movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy.

common iliac arteries

part of systemic circulation

stem off of aorta

sends blood to almost every organ of body

brachiocephalic artery

branches off into right subclavian and right common carotid

only on right side of body

coronary circulation

subclavian artery

supplies blood to upper limbs

breaks into internal thoracic, vertebral and thyrocervical

common carotid artery

divides into internal and external carotid arteries

L rises from aortic arch

what arteries provide blood to the brain?

internal carotid arteries and vertebral arteries

circle of willis

A circle of arteries at the base of the brain that supply blood to the brain

what veins combine to form the superior vena cava?

left and right brachiocephalic veins

which veins combine to form the inferior vena cava?

R and L common iliac veins

what branches does the arch of aorta have?

brachiocephalic, L subclavian and L common carotid

what artery supplies blood to the frontal lobe?

anterior cerebral artery

what artery supplies blood to the parietal and temporal lobes?

middle cerebral artery

internal jugular vein

primarily drains blood from the brain, receives the superficial facial vein, and empties into the subclavian vein

external jugular vein

Drains blood from the more superficial portions of the head, scalp, and cranial regions, and leads to the subclavian vein

external iliac vein

formed from femoral vein

drains legs

flows into common iliac vein

internal iliac vein

drains pelvic organs and integument

flows into common iliac vein

What are the beginning positions of the cardiac cycle?

A and V are in diastole

AV valves are open

semilunar valves are closed

What happens in atrial systole and diastole?

A contracts (P wave on ECG)

pressure rises and pumps blood to ventricles via AV valves

100 ms

what happens in ventricular systole phase 1?

Ventricles contract (QRS on ECG)

pressure rises but not enough to open valves

blood flows back to atria and closes AV valves

ventricles hold 130 mL before ejecting

What happens in ventriclular systole phase 2?

Ventricles contract

pressure rises enough this time to open semilunar valves

about 70-80 mL of blood is pumped out

what happens in ventricular diastole phase 1?

ventricles relax (T wave on ECG)

pressure drops and blood flows back into heart

semilunar valves close

no volume change

what happens in ventricular diastole phase 2?

pressure drops below atria

AV valves open to let blood flow from A to V

what makes the first heart sound?

closing of the AV valves in ventricle contraction

What are the 5 things that influence blood flow and pressure?

Cardiac output

Compliance

Volume of blood

Viscosity of blood

Blood vessel length and diameter

what is plasma composed of?

92% water, 7% proteins, the rest is all 1% (gases, minerals, carbs and lipids, waste products, vitamins, hormones and drugs)

describe red blood cells

1) contain hemoglobin

2) have no nucleus

3) biconcave structure

4) highly adapted

describe white blood cells

Leukocytes that contain nuclei and are the source of DNA in the blood sample

What are the steps of hemostasis?

1. vascular spasm (contraction of smooth muscle in blood vessel wall)

2. platelet plug formation (temporary seal against blood loss)

3. coagulation (blood clotting)

neutrophils

most abundant WBC granulocyte

multilobe nucleus

first defenders at inflammation site

have digestive chemical

arises from myeloid stem cells

eosinophils

enzymes that counteract histamine effect

phagocytize antigen-antibody complexes, pathogens and parasites

bi lobed granulocytes

basophils

bi/tri lobed nucleus granulocyte

have heparin, histamine and seratonin

related to allergiesw

lymphocytes

A type of white blood cell that make antibodies to fight off infections

agranulocyte

Monocytes

An agranular leukocyte that is able to migrate into tissues and transform into a macrophage.

Lymphocyte- NKC

attack tumor cells

lyphocyte-T cells

cell mediated adaptive immunity

lymphocyte- B cell

antibody mediated innate immune response

where is the endothelium?

tunica intima

type O blood

lacks A and B antigens

what does the sinoatrial node do in circulation of blood?

signals cause the V to contract and AV valves to close

what is afterload?

force the heart has to overcome to pump blood

In the first stage of hemostasis, the muscles in the blood vessel wall do what?

contract

In the second stage of hemostasis, which cells aggregate and form a plug?

platelets

In the third stage of hemostasis, the blood coagulates and forms a clot. The clotting is stimulated and regulated by clotting factors.

In addition to clotting enzymes, which substances are needed to control blood clots?

vitamin K and calcium ions

Red blood cells or erythropoietin cells arise from stems cells that are called

hemocytoblasts

how long does it take to become a mature erythrocyte? how long is their life span?

2 days

120 days

what is preload?

Degree of the stretch in ventricular muscle

Where does the respiratory zone start?

terminal bronchioles

what do type 1 alveolar cells do?

allow diffusion of CO2 and O2

what do type 2 alveolar cells do?

secrete pulmonary surfactant

What do alveolar macrophages do?

removes debris and pathogens

What does the trachea do?

transports mucus and inhaled particles out of the lungs

divides into 2 primary bronchi

how is the R primary bronchus different from the L?

It is more vertical, shorter and wider than L

What are the layers of the pleurae surrounding the lungs?

visceral (above)

parietal (connects to thoracic wall)

what are type one cells in the alveolar wall?

squamous epithelial cell

97% of alv surface area

highly permeable to gas

what are type 2 cells in the alveolar wall?

interspersed in type 1

secrete pulmonary surfactant

what are alveolar machrophages in the alveolar wall?

phagocytic cell of immune system

removes debris and pathogens

what muscles are used with a forced inhalation?

scalenes, traps, diaphragm and external intercostal muscles

What muscles are used with forced exhalation?

abs, internal intercostal, diaphragm and external intercostal muscles

where are the frontal sinuses?

center of eyebrows

Where are the maxillary sinuses?

cheek bones, under eyes

sinus infection hub

Where are the sphenoid sinuses?

between eyes, nose bridge

nasopharynx

region of the pharynx at the back of the nose and above the soft palate

oropharynx

the area directly posterior to the mouth

passage for air and food

2 sets of tonsils

laryngopharynx

region of the pharynx below the epiglottis that includes the larynx

route for ingested material and air

larynx

voice box; passageway for air moving from pharynx to trachea; contains vocal cords

regulates volume of air that enters and leaves lungs

Epiglottis

a flap of cartilage at the root of the tongue, which is depressed during swallowing to cover the opening of the windpipe.

Trachea

a large membranous tube reinforced by rings of cartilage, extending from the larynx to the bronchial tubes and conveying air to and from the lungs; the windpipe.

what is the order of structures through which air will flow as it enters the lungs?

Tertiary bronchi, terminal bronchioles, respiratory bronchioles, alveolar ducts

what are the 3 factors for easy breathing?

surface tension of the alveolar fluid

lung compliance

airway resistance

Which factor is responsible for the difference in pitches of the sound produced by the vocal cords?

Tightening and slacking of the membranous folds

What affects hemoglobins affinity for O2

high PCO2

high PO2

increase in temperature

low tissue pH

carbaminohemoglobin transport

How is gas affected by pressure?

moves from high to low pressure

what happens during inhalation?

thoracic cavity expands

external intercostal muscles contract

diaphragm contracts

what happens during exhalation

thoracic cavity reduces

external intercostal muscles and diaphragm relaxes

Which part of the brain signals the respiratory center to increase respiration during times of stress?

limbic system

Which part of your brain allows you to have voluntary control over your breathing in order to hold your breath underwater?

cerebral cortex

What produces hydrochloric acid?

parietal cells of the stomach

HCI activates pepsin and kills bacteria

what produces intrinsic factor?

Parietal cells of the stomach

IF absorbs vitamin B12 in small intestine

What do chief cells secrete?

pepsinogen

where is gastrin produced and what is it's purpose?

in stomach mucosa in G cells

promotes gastric emptying and intestinal muscle contraction

relaxes ileocecal valve and triggers mass movements in large intestine

where is ghrelin produces and what does it do?

in stomach mucosa

regulates food intake

where is histamine produced and what does it do?

stomach mucosa

stimulates parietal cells to release HCI

where is serotonin produced and what does it do?

gastric mucosa

contracts stomach muscle

where is somatostatin produced and what does it do?

stomach mucosa in D cells

restricts gastric and pancreatic secretions

reduces intestinal absorption in small intestine

what cells secrete insulin and glucagon

Islets of Langerhans

where is lingual lipase produced and what does it break down?

lingual glands

triglycerides into free fatty acids

where is salivary amylase produced and what does it break down?

salivary glands

polysaccharides into oligo and disaccharides

where is a-dextrinase produced and what does it break down?

small intestine

a-dextrin into glucose

where is enteropoptidase produced and what does it break down?

small intestine

trypsinogen into trypsin

where is lactase produced and what does it break down?

small intestine

lactose into glucose and galactose

where is maltase produced and what does it break down?

small intestine

maltose into glucose

where is sucrase produced and what does it break down?

small intestine

sucrose into fructose and glucose