Exam 2 Review- Lymphatic System, Immunity, and Respiratory System: Key Concepts, Structures, & Application

What are the two main functions of the lymphatic system?

Support immunity and return excess tissue fluid to the bloodstream to maintain fluid balance.

Put the lymphatic passageways in order from smallest to largest.

Lymphatic capillaries → lymphatic vessels → lymphatic trunks → lymphatic ducts.

Which blood vessels do lymphatic vessels resemble?

Veins; both have three tunics and valves that help prevent backflow.

Trace lymph from the right leg to the bloodstream.

Right lumbar trunk → cisterna chyli → thoracic duct → left subclavian vein at its junction with the left internal jugular vein.

Which lymph node group receives lymph from the head and neck?

Cervical lymph nodes.

What do tonsils help protect against?

Pathogens that enter through inhalation or ingestion.

Where is red bone marrow located?

In spaces within spongy bone.

Where are B lymphocytes generated and where do they mature?

They are generated and mature in red bone marrow.

Where do T lymphocytes mature?

In the thymus.

What are Peyer patches and where are they located?

Aggregated lymphoid nodules in the small intestine; they are part of mucosa-associated lymphoid tissue, or MALT.

Where is the spleen located?

In the left upper abdominal quadrant.

What are the main functions of the spleen?

Filter blood, recycle aged red blood cells, serve as a platelet reservoir, and house immune cells.

Which filters blood and which filters lymph: spleen or lymph nodes?

The spleen filters blood; lymph nodes filter lymph.

Does the spleen have an outer cortex and inner medulla?

No. Its tissue is organized into red pulp and white pulp.

What cells are found in the white pulp of the spleen?

Lymphocytes and macrophages.

What are splenic trabeculae?

Inward extensions of the spleen capsule that help support and divide its tissue.

Which vessels bring blood to and drain blood from the spleen?

The splenic artery brings blood in; the splenic vein drains blood out.

What is the main goal of an immune response?

Destroy or inactivate pathogens and foreign material.

How do innate and adaptive immunity differ?

Innate defenses are nonspecific; adaptive defenses target specific antigens and can form memory cells.

What is an external innate defense?

A barrier such as intact skin that helps prevent pathogens from entering.

A bacterium enters through a cut and a neutrophil destroys it. Which defenses are involved?

The external innate barrier failed, but an internal innate defense succeeded.

Is inflammation specific to one antigen?

No. It is a nonspecific innate response that occurs in vascularized tissue.

Why is the first adaptive response slower than an innate response?

Specific lymphocytes must recognize the antigen, become activated, and multiply.

Which immune cells attack without the antigen specificity of B and T cells?

Natural killer cells; they are part of innate immunity.

What is humoral immunity?

Antibody-mediated adaptive immunity involving B lymphocytes and their antibody-producing plasma cells.

What are the effectors of antibody-mediated immunity?

Antibodies.

What is cell-mediated immunity?

Adaptive immunity involving T lymphocytes, including cytotoxic T cells that attack infected or abnormal cells.

Which lymphocytes recognize targets displaying antigen on MHC class I?

Cytotoxic T lymphocytes, also called CD8 T cells.

What happens after a T lymphocyte is activated?

It proliferates to form clones, including effector cells and memory cells.

What do memory lymphocytes do?

Help produce a faster and stronger response to a later encounter with the same antigen.

What is opsonization?

Coating or marking a target so phagocytes can recognize and engulf it more easily.

How does an antibody help a phagocyte during opsonization?

The antibody binds the target; the phagocyte binds the antibody Fc region.

What is active immunity?

Protection produced by your own immune response after exposure to an antigen, such as infection or vaccination.

What is passive immunity?

Protection from antibodies made elsewhere and transferred to you.

Why is receiving antivenom an example of passive immunity?

The patient receives ready-made antibodies rather than making them through their own response.

Which are immune defenses: antibody production, direct cell attacks, memory formation, or antigen replication?

Antibody production, direct cell attacks, and memory formation. Antigen replication is not an immune defense.

What is the conducting zone of the respiratory system?

The air passages that move air; it includes the nasal cavity, larynx, trachea, bronchi, and terminal bronchioles.

What structures belong to the respiratory zone?

Respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.

Are terminal bronchioles part of the respiratory zone?

No. They are part of the conducting zone.

Which alveolar cells make surfactant?

Type II alveolar cells.

What does surfactant do?

Reduces surface tension and helps prevent alveolar collapse.

What is the hilum of a lung?

An indented area where bronchi, pulmonary vessels, lymphatic vessels, and nerves pass.

Which lung is larger and wider?

The right lung.

How do parietal and visceral pleura differ?

Parietal pleura lines the internal chest wall; visceral pleura covers the lung surface.

How does intrapleural pressure help keep lungs expanded?

It is lower than intrapulmonary pressure, helping maintain an outward distending pressure on the lungs.

What does Boyle's law say about volume and pressure?

At constant temperature, increasing gas volume decreases pressure; decreasing volume increases pressure.

Describe quiet inspiration using muscles, volume, and pressure.

The diaphragm and external intercostals contract; thoracic volume increases and alveolar pressure falls below atmospheric pressure, so air enters.

Describe quiet expiration using muscles, volume, and pressure.

The diaphragm and external intercostals relax; elastic recoil reduces thoracic volume and raises alveolar pressure above atmospheric pressure, so air leaves.

Why does air flow out of the lungs during expiration?

Intrapulmonary pressure is greater than atmospheric pressure.

What is inspiratory reserve volume?

The extra air that can be forcibly inhaled after a normal inspiration.

What is residual volume?

Air remaining in the lungs after maximal expiration.

What is anatomic dead space?

Air in conducting passages where gas exchange does not occur.

What is physiologic dead space?

Anatomic dead space plus alveolar air that does not effectively participate in gas exchange.

Which dead-space term includes ineffective alveolar gas exchange in lung disease?

Physiologic dead space; anatomic dead space refers to the conducting airways.

What is ventilation?

Movement of air into and out of the lungs.

What is pulmonary gas exchange?

Exchange of oxygen and carbon dioxide between alveolar air and pulmonary blood.

What is tissue gas exchange?

Exchange of oxygen and carbon dioxide between systemic blood and body tissues.

What determines the direction in which a gas diffuses?

Its partial-pressure gradient; it moves from higher to lower partial pressure.

Which way does oxygen move during pulmonary gas exchange and why?

From alveoli into blood because alveolar oxygen partial pressure is higher.

Which way does oxygen move during tissue gas exchange?

From blood into tissues.

Trace carbon dioxide from the tissues to exhalation.

Carbon dioxide moves from cells into blood, travels to the lungs, diffuses into alveoli, and is exhaled.

How does increased local alveolar oxygen affect pulmonary arterioles?

They dilate, increasing local perfusion to help match blood flow with ventilation.

What is perfusion?

Blood flow through tissue; in the lungs it supplies capillaries for gas exchange.

Why is hemoglobin important for oxygen transport?

Oxygen has low solubility in water, so little can be transported dissolved in plasma.

About what percentage of blood oxygen is carried by hemoglobin?

About 98%.

About 23% of blood carbon dioxide attaches to which part of hemoglobin?

The globin portion, rather than the heme iron.

What is the major form of carbon dioxide transport in blood?

Bicarbonate ions; a smaller amount binds globin and a small amount is dissolved.

What kind of chemoreceptors are in the carotid bodies?

Peripheral chemoreceptors that respond to changes in blood oxygen and hydrogen ion concentration; they also respond to carbon dioxide.

Which respiratory center smooths transitions between inspiration and expiration?

The pontine respiratory center, historically called the pneumotaxic center.

How can airway obstruction and hypoventilation affect oxygen and pH?

They can cause hypoxia and carbon dioxide retention, producing respiratory acidosis.

What happens to carbon dioxide and pH during hypoventilation?

Carbon dioxide rises and pH falls.

What happens to carbon dioxide and pH during hyperventilation?

Carbon dioxide falls and pH rises, producing respiratory alkalosis.

Why can hyperventilation cause dizziness or faintness?

Low carbon dioxide can constrict cerebral blood vessels and reduce blood flow to the brain.

Sequence oxygen use and carbon dioxide removal.

Inhale oxygen → transport oxygen to cells → cells use oxygen and make carbon dioxide → transport carbon dioxide to lungs → exhale carbon dioxide.

Apply it: If the diaphragm contracts, what happens to chest volume, alveolar pressure, and airflow?

The diaphragm flattens, chest volume increases, and alveolar pressure falls below atmospheric pressure, so air moves in.

Apply it: A student says the diaphragm contracts to push air out during quiet expiration. What needs correcting?

During quiet expiration, the diaphragm relaxes. Elastic recoil decreases chest volume, raises alveolar pressure, and moves air out

Apply it: Alveolar pressure equals atmospheric pressure. Which direction does air move?

There is no net airflow because there is no pressure difference. Airflow requires a pressure gradient.

Apply it: If the chest expands but alveolar pressure has not yet fallen below atmospheric pressure, will air move in?

No. Expansion produces inspiration by lowering alveolar pressure below atmospheric pressure; air moves because of that pressure difference.

Apply it: Why does increasing chest volume lower alveolar pressure?

The gas has more space available. Boyle's law describes the inverse relationship between gas volume and pressure.

Apply it: Type II alveolar cells produce less surfactant. What becomes harder and why?

Keeping alveoli open becomes harder because surface tension increases, making alveoli more likely to collapse.

Apply it: Why can air in a terminal bronchiole count as anatomic dead space even though the airway is healthy?

Terminal bronchioles conduct air but do not exchange gases. Dead space does not always mean damaged tissue.

Apply it: Air reaches an alveolus, but little blood flows past it. Why is gas exchange less effective?

Ventilation brings air, but perfusion brings blood to pick up oxygen and deliver carbon dioxide. Efficient exchange needs both.

Apply it: Why does a larger amount of dead-space ventilation reduce the usefulness of each breath?

More of the inhaled air fails to participate effectively in gas exchange, leaving less useful ventilation for the same breath size.

Apply it: A person takes a normal breath in and then inhales as deeply as possible. What is the extra inhaled air called?

Inspiratory reserve volume. It is the additional air inhaled beyond a normal inspiration.

Apply it: Oxygen partial pressure is higher in an alveolus than in nearby blood. Predict oxygen movement.

Oxygen diffuses from the alveolus into the blood, down its partial-pressure gradient.

Apply it: Body cells continually use oxygen. How does that help oxygen leave the blood?

Using oxygen keeps tissue oxygen partial pressure lower than blood oxygen partial pressure, supporting diffusion into tissues.

Apply it: Why does oxygen move into blood at the lungs but out of blood at the tissues?

The partial-pressure gradients differ. Alveoli have more oxygen than arriving blood; arriving systemic blood has more oxygen than the tissues.

Apply it: A well-ventilated alveolus has increased local oxygen. How do nearby pulmonary arterioles respond?

They dilate, allowing more blood flow to that region and helping match perfusion to available oxygen.

Apply it: Why can normal airflow alone fail to provide normal oxygen delivery to body cells?

Oxygen delivery also depends on alveolar gas exchange, blood flow, and sufficient hemoglobin to carry oxygen.

Apply it: If hemoglobin is greatly reduced, why can oxygen transport decrease even when the lungs work normally?

Most oxygen is carried on hemoglobin. Less hemoglobin means less oxygen-carrying capacity; dissolved oxygen contributes only a small amount.

Apply it: A student says oxygen and carbon dioxide attach to the same part of hemoglobin. What is the correction?

Oxygen binds to iron in heme. Carbon dioxide carried on hemoglobin binds to the globin protein portion.

Apply it: Why does carbon dioxide retention lower blood pH?

Carbon dioxide reacts with water to form carbonic acid, which can release hydrogen ions. More hydrogen ions means lower pH.

Apply it: A person hypoventilates and retains carbon dioxide. Predict the pH change and name the imbalance.

Blood pH falls, producing respiratory acidosis. The cause is inadequate carbon dioxide removal by breathing.

Apply it: A person breathes more than needed to remove the carbon dioxide being produced. Predict carbon dioxide and pH changes.

Carbon dioxide falls and pH rises. This is hyperventilation and can cause respiratory alkalosis.

Apply it: Why can someone feel dizzy while hyperventilating even though plenty of air is moving?

Excess carbon dioxide removal can constrict cerebral blood vessels and reduce blood flow to the brain. More airflow does not always mean better function.

Apply it: Carotid-body receptors detect low blood oxygen. Why is this information useful for breathing control?

The receptors send information to brainstem respiratory centers, which can increase breathing to help restore adequate oxygen.

Apply it: If excess tissue fluid is not returned to the blood by lymphatic vessels, what can happen?

Fluid can accumulate in tissues and cause swelling, or edema. Lymphatic drainage helps maintain fluid balance.

Apply it: Why does lymph from the right leg enter the thoracic duct rather than the right lymphatic duct?

The thoracic duct drains both lower limbs and most of the body. The right lymphatic duct drains the right upper region.

Apply it: A student says the spleen filters lymph because it is a lymphatic organ. What is the correction?

The spleen is a lymphatic organ that filters blood. Lymph nodes filter lymph; organ category does not mean identical function.

Apply it: Bacteria enter through damaged skin and are engulfed by neutrophils before a specific antibody response develops. Which defense is working?

Internal innate immunity. Neutrophils act nonspecifically after the external skin barrier has been breached.