Lecture Test 2 Study Guide
A&P II, Dr. Bailey
Chapter 21- Blood Vessels
The tunica intima is the innermost layer of a blood vessel The muscular layer in the wall of a blood vessel is
the tunica media. The layer between the tunica media and the tunica externa in a large artery is the external
elastic membrane. In large arteries, the thick layer of elastic fibers is called the internal elastic membrane.
Compared to arteries, veins have thinner walls.
The large vessels that return blood to the heart are called veins. Venae cavae are the largest of vein. Veins hold
the largest percentage of the blood supply.
Venoconstriction reduces the amount of blood within the venous system, which increases the volume in the
arterial and capillary systems. Vasodilation does the opposite.
Venous valves are responsible for channeling blood toward the heart.
As blood travels from arteries to veins pressure drops.
Blood flow to a tissue will increase if the arterioles dilate.
An artery is the vessel with the highest blood pressure. Blood pressure is lowest in the veins.
Blood viscosity, vessel diameter, turbulence, vascular resistance all affect blood flow through the body.
Turbulent blood flow occurs, when there are irregularities in the vessel wall, at high flow rates, when there are
sudden changes in vessel diameter, when blood pressure is excessively high.
The force that moves fluid out of capillaries is hydrostatic pressure whereas the opposing force that moves fluid
into capillaries is osmotic pressure.
Chapter 22-The Lymphatic System
Lymphocytes provide an adaptive or specific defense known as the immune response.
The primary function of the lymphatic system is defending the body against both environmental hazards and
internal threats.
In general, lymphocytes spend most of their time in lymphatic tissue. Lymphocytes may be found in the
following tissues or organs: tonsils, spleen, lymph nodes, thymus
Most of the lymph returns to the venous circulation by way of the thoracic duct. The thoracic duct drains
lymph from all of the following regions, except the right upper extremity, right chest, right breast.
The cells responsible for humoral immunity are the B cells.
The medullary cords of a lymph node contain B lymphocytes and plasma cells.
Lymphocytes that destroy foreign cells or virus-infected cells and responsible for cellular immunity are
cytotoxic T cells.
The term lymphadenopathy refers to a chronic or excessive enlargement of lymph nodes.
The cells responsible for the production of circulating immunoglobulins are plasma cells.
Chapter 23-The Respiratory System
The nasal cavity, pharynx, and larynx constitute the conducting portion of the airway.
Components of the upper respiratory system include the nose, nasal cavity, pharynx. paranasal sinuses. Air
entering the body is filtered, warmed, and humidified by the upper respiratory tract.
The larynx, trachea, bronchi, and bronchioles all make up the lower respiratory tract.
The respiratory mucosa consists of epithelium and underlying layer of areolar tissue.
The respiratory defense system is important because it helps filter the air, helps warm the air, keeps out debris,
keeps out pathogens.
The nasopharynx is divided from the rest of the pharynx by the soft palate. The nasal cavity is separated from
the oral cavity by the hard palate.
The pharynx is shared by the respiratory and digestive systems.
The portion of the pharynx that receives both air and food is the oropharynx.
The larynx contains 9 cartilages.
The glottis is the opening to the larynx. The vocal folds are located within the larynx.
The elastic cartilage that covers the opening to the larynx during swallowing is the epiglottis.
The largest cartilage of the larynx is the thyroid cartilage.
The airway that connects the larynx to the bronchial tree is the trachea.
The primary bronchi branch from the trachea at the carina.
The C shape of the tracheal cartilages is important because large masses of food can pass through the esophagus
during swallowing.
The following is a list of airways and the order in which air passes through:
primary bronchus → secondary → bronchus → bronchioles→ terminal bronchiole→ respiratory bronchiole
→ alveolar duct → alveoli
Lab Test I Study Guide