Week 5-8 & Additional

Upper Respiratory Tract

Includes nose, nasal cavity, paranasal sinuses, and nasopharynx.

Lower Respiratory Tract

Includes trachea, bronchial tree, and lungs.

Conducting Zone

Nose, pharynx, larynx, trachea, bronchi, and up to terminal bronchioles, responsible for air passage.

Respiratory Zone

Respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli, where gas exchange occurs.

Respiratory Mucosa

Lined mostly with pseudostratified columnar ciliated epithelium.

Cilia (on mucosal cells)

Beat in one direction to move mucus upward to the pharynx for removal.

Nasal Septum

Separates the interior of the nose into two cavities.

Bony Hard Palate

Formed by maxillae and palatine bones, separates oral and nasal cavities.

Pharynx (Throat)

A 12.5 cm long passageway for food, liquids, and air distribution, divided into nasopharynx, oropharynx, and laryngopharynx.

Pharyngeal Tonsils and openings of auditory tubes

Open into nasopharynx

Palatine Tonsils

Tonsils found in the oropharynx.

Larynx

Structure formed by several pieces of cartilage which form framework that functions in air distribution and voice production.

Thyroid Cartilage

The largest piece of cartilage in the larynx, commonly known as Adam's apple.

Epiglottis

A cartilage flap that partially covers the opening into the larynx during swallowing.

True Vocal Cords

Structures within the larynx responsible for voice production.

Trachea

A tube about 4.5 inches long, extending from the larynx into the thoracic cavity, held open by C-shaped cartilage rings; passage way for air to move to and from lungs

Bronchi, Bronchioles, and Alveoli

Branches of the trachea (right and left) that extend into the lungs, distributing air.

Right Bronchus

Wider and shorter than the left, making it a common entry point for foreign bodies from the trachea.

Bronchioles

Smaller and smaller tubes branching from the bronchus, ending in microscopic alveolar sacs.

Alveoli

Microscopic air sacs at the end of bronchioles where gas exchange between air and blood occurs.

Type I Alveolar Cell

The typical cell making up the alveolar wall.

Type II Alveolar Cells

Cells that produce surfactant, which reduces surface tension in the alveoli.

Apex (of the Lung)

The narrow upper part of each lung, located under the collarbone.

Base (of the Lung)

The broad lower part of each lung that rests on the diaphragm.

Right Lung

Composed of 3 lobes.

Left Lung

Composed of 2 lobes.

Pleura

A moist, smooth, slippery membrane lining the chest cavity and covering the outer surface of the lungs, reducing friction during breathing.

Diaphragm Contraction

Increases the size of the thoracic cavity, causing pressure inside to drop and air to flow into the lungs (pulmonary ventilation).

External Respiration

Exchange of gases in the lungs, where oxygen moves from alveoli into lung capillaries and carbon dioxide moves out into alveolar air.

Internal Respiration

Exchange of gases in the tissues, where oxygen moves from tissue capillary blood into tissue cells and carbon dioxide moves from tissue cells into tissue capillary blood.

Medulla Oblongata

The brain region controlling the basic respiratory rhythm.

Pons

The brain region that controls the rate of breathing in conjunction with the Medulla.

Chemoreceptors

Sensors that detect changes in CO2, O2, and pH to adjust breathing.

Mechanoreceptors

Receptors that prevent overinflation of the lungs and respond to physical irritants.

Higher Centers (Respiration)

Regions in the cerebrum and hypothalamus that influence respiration.

Division of Respiratory System

Separated into conducting zone and respiratory zone

Sinuses that drain into the nose

Frontal, Maxillary, Spenodial, and Ethmoidal

Functions of the Nose

Warms and moistens inhaled air; contains sense organs of smell

What has openings into pharynx?

Two nasal cavities, mouth, esophagus, laryns, and auditory tubes

Thyroid, Cricoid, and Epiglottis (Unpaired or Paired)

Unpaired 

Arytenoids, Corniculate, and Cuneiform (Unpaired or Paired)

Paired

What stretches across interior of larynx?

Vocal cords and Vestibular Folds

Microscopic Alveolar Sacs

The walls of which are made up of alveoli

Bronchi and Bronchioles

Air distribution; passageway for air to move to and from alveoli

Lungs and Pleura Structure

Large enough to fill chest cavity, except for middle space occupied by heart and large blood vessels

Endocrine glands

Ductless glands that secrete chemicals called hormones into the blood.

Hormones

Chemicals secreted by endocrine glands that perform general functions of communication and control.

Target cells

Cells acted on by hormones.

Feedback loops

Mechanism that controls the regulation of hormone secretion.

Negative feedback

Mechanisms that reverse the direction of a change in a physiological system; regulates most hormonal secretion (Negative feedback loop) EX: Insulin, TSH, ACTH

Positive feedback

Uncommon mechanisms that amplify physiological changes, such as the action of Oxytocin.

Hypothalamus

Responsible for the production of ADH, oxytocin, and regulatory hormones (releasing and inhibitory hormones).

Pituitary gland (Hypophysis)

Located in the sella turcica (Pituitary fossa) and attached to the hypothalamus by a stalk called the infundibulum, it is divided into Anterior and Posterior Pituitary Glands.

Anterior Pituitary Gland (Adenohypophysis)

The front lobe of the pituitary gland produces and secretes hormones like Thyroid-Stimulating Hormone(TSH), Adrenocorticotropic Hormone (ACTH), Follicle-Stimulating Hormone (FSH), Luteinizing Hormone (LH), Growth Hormone (GH), and Prolactin (Lactogenic Hormone).

Thyroid-stimulating hormone (TSH)

Target Organ: Thyroid Gland | Function: Hormone from the anterior pituitary that stimulates Thyroid gland

Adrenocorticotropic hormone (ACTH)

Target Organ: Adrenal Cortex | Function: Hormone from the anterior pituitary that stimulates the growth of the adrenal cortex and production of its hormones.

Follicle-stimulating hormone (FSH)

Target Organ(s): Ovarian follicles in females; Seminiferous tubules in men | Function: Hormone from the anterior pituitary that stimulates maturation of ovarian follicles in females and spermatogenesis in males.

Luteinizing hormone (LH)

Target Organ(s): Ovaries/Testes | Function: Hormone from the anterior pituitary that stimulates ovulation in females and secretion of testosterone in males.

Growth hormone (GH)

Target Organ: Musculoskeletal System | Function: Hormone from the anterior pituitary that promotes growth and development.

Prolactin (lactogenic hormone)

Target Organ: Mammary Gland (Breast) | Function: Hormone from the anterior pituitary that stimulates milk production.

Posterior Pituitary Gland (Neurohypophysis)

Hormones are actually produced by the hypothalamus but are released through the posterior pituitary gland. (Oxytocin and Antidiuretic Hormone (ADH))

Oxytocin

Hormone released by the posterior pituitary that targets the uterus for childbirth and the breast for milk flow.

Antidiuretic Hormone (ADH)

Hormone released by the posterior pituitary that targets the kidneys for regulation of body fluid in response to electrolyte concentration changes or blood volume/pressure falls. 

Diabetes insipidus

A syndrome due to underproduction of ADH.

Pars intermedia

A part of the pituitary gland that secretes MSH (Melanin stimulating Hormone).

Thyroid gland

The largest endocrine gland, located in the neck, bilobed with an isthmus; requires iodine for hormone production and controls cellular metabolism; works under the control of TSH secreted by anterior pituitary gland. 

Triiodothyronine (T3)

A major hormone of the thyroid gland that controls cellular metabolism and the growth and development of nervous and skeletal systems. Target Cells: All Body Cells, Skeletal and Nervous System

Tetra-iodothyronine (T4) (Thyroxine)

A major hormone of the thyroid gland with functions similar to T3, controlling cellular metabolism and growth/development.

Calcitonin

Hormone secreted by the thyroid gland that lowers blood calcium levels, targeting the intestine, bone, and kidneys.

Parathyroid gland

Located in the neck, behind the thyroid (two pairs); secretes Parathyroid hormone (PTH) which is antagonistic to Calcitonin.

Parathyroid hormone (PTH)

Hormone secreted by the parathyroid gland that increases calcium levels in the blood by targeting osteoclasts, renal tubules, and the intestine.

Adrenal glands (Suprarenal glands)

Paired glands located above the kidneys, two in one gland, composed of an adrenal cortex and an adrenal medulla.

Adrenal Cortex

The outer part of the adrenal gland, under the control of ACTH, is secreted by the anterior pituitary gland; 3 zones called Zona Glomerulosa, Zona Fasiculata, and Zona Resticulate that secrete mineralocorticoids, glucocorticoids, and androgens.

Mineralocorticoids (Aldosterone)

Hormones primarily from the zona glomerulosa (OUTER) of the adrenal cortex that act as Na and H2O saving hormones, targeting renal tubules.

Glucocorticoids (Cortisol)

Hormones primarily from the zona fasciculata (MIDDLE) of the adrenal cortex that increase blood glucose levels, act as anti-inflammatory agents, and have anti-immunity effects targeting the liver and immune system.

Androgens (adrenal cortex)

Hormones from the zona reticulata (INNER) of the adrenal cortex that target the reproductive system which effects libido.

Adrenal Medulla

The inner part of the adrenal gland, part of the sympathetic nervous system, secreting epinephrine (adrenaline) and norepinephrine (Noradrenalin).

Epinephrine (Adrenaline) and Norepinephrine (Noradrenalin)

Hormones secreted by the adrenal medulla that help the body resist stress by intensifying and prolonging sympathetic stimulation effects- increased epinephrine secretion is the first edocrine response to stress

Pancreas

located between the stomach and small intestine: A mixed gland in the abdominopelvic cavity with both exocrine (digestive enzymes) and endocrine activities (Islets of Langerhans).

Islets of Langerhans

The endocrine part of the pancreas, containing alpha, beta, and delta cells.

Glucagon

Hormone secreted by alpha cells in the pancreas that increases blood glucose levels.

Insulin

Hormone secreted by beta cells in the pancreas that lowers blood glucose levels.

Somatostatin

Hormone secreted by delta cells in the pancreas that inhibits the release of other hormones.

Ovaries

Female sex glands containing ovarian follicles and corpus luteum, which secrete various hormones.

Estrogen (feminizing hormone)

Hormone secreted by ovarian follicles that promotes development and maturation of breasts, external genitalia, adult female body contours, and initiation of the menstrual cycle.

Corpus luteum

A structure within the ovary that secretes progesterone, relaxin, and a small amount of estrogen.

Progesterone

Hormone secreted by the corpus luteum that prepares the endometrium for pregnancy and promotes proliferation of milk-secreting ducts in the breast.

Relaxin

Hormone secreted by the corpus luteum, primarily targeting the pubic symphysis, uterus, and mammary glands.

Testes (Interstitial cells)

Male sex glands whose interstitial cells produce androgens, primarily testosterone.

Testosterone (masculinizing hormone)

Hormone produced by interstitial cells of testes that promotes maturation of external genitalia, growth of facial hair, voice changes at puberty, and development of male musculature and body contours.

Thymus

Located in the anterior mediastinum; essential before birth and early childhood; site for lymphocyte development; produces thymosin and thymopoietin.

Lymphocytes (Thymus)

Immune cells whose development is supported by the thymus, playing a great role in body defenses.

Thymosin and Thymopoietin

Hormones produced by the thymus that are essential for the development of other lymphoid organs.

Pineal Gland

A small structure attached to the posterior end of the thalamus (known as the third eye); receives fibers from optic radiation; stimulated by darkness, inhibited by light; secretes melatonin and plays a role in circadian rhythm.

Melatonin

Hormone secreted by the pineal gland that induces sleep and plays a role in circadian rhythm.

Erythropoietin

Hormone released by the kidney when the oxygen content of the blood becomes too low, stimulating red blood cell production.

Menopausal women

There is a decline in the concentration of reproductive hormones.

The Nervous system is divided into

central and peripheral nervous system

The central nervous system (CNS) consists of the

brain and spinal cord

The peripheral nervous system (PNS) consists of both

cranial & spinal nerves