Upper respiratory system

nose, nasal cavity, sinuses, and pharynx (down to the epiglottis)

Lower respiratory system

Larynx, trachea, bronchi, bronchioles, lungs, and alveoli

Nose/Nasal Cavity

The entry point for air; nasal conchae creates turbulence to warm, humidify, and filter incoming air. The paranasal sinuses connect to the nasal cavity

Pharynx (throat)

A muscular passageway divided into three regions

- Nasopharynx: posterior to the nasal cavity

- Oropharynx: posterior to the oral cavity

- Laryngopharynx: posterior to the larynx

Bronchi/Bronchioles

The trachea branches into left and right primary bronchi, which enter the lungs and continue to branch into smaller bronchioles

Conducting portion

All structures from the nose/mouth to the terminal bronchioles. This portion filters, warms, and humidifies air but does not perform gas exchange

Gas exchange

Oxygen diffuses from the alveoli into the blood

Carbon dioxide diffuses from the blood into the alveoli

Pseudostratified Ciliated Columnar Epithelium

Specialized respiratory epithelium that lines the conducting portion; coated with a sticky mucus

Mucociliary elevator

Cilia constantly beat in a coordinated wave, moving the mucus and any trapped debris and pathogens upward toward the pharynx; prevents contaminants from reaching the delicate lungs

Type I Alveolar Cells

Thin, squamous epithelial cells that form the primary structure of the alveolar wall; main sites of gas exchange

Type II Alveolar Cells

Provide surfactant, a detergent-like substance that reduces surface tension and prevents the alveoli from collapsing after exhalation

Bronchial arteries

Supplies the lungs with oxygenated blood

Visceral Pleura

Inner layer that directly covers the surface of the lungs

Pleural Cavity

Houses the lungs; contains a small amount of pleural fluid that reduces friction during breathing

Parietal Pleura

The outer layer that lines the inside of the thoracic wall, the mediastinum, and the superior surface of the diaphragm

Pulmonary Ventiliation

Breathing, involves a pressure gradient between the atmosphere and the alveoli

Primary muscles in puliminary ventilation

Diaphragm and intercostal muscles

Inhalation

The diaphragm contracts and flattens

The external intercostal muscles contract, lifting the ribcage

Increased volume of thoracic cavity

Decreased intra-pulmonary pressure below atmospheric pressure

Exhalation

Diaphragm and external intercostal muscles relax

Thoracic cavity volume decreases

Increased intra-pulmonary pressure above atmospheric pressure

Medulla Oblongata

In the brainstem; acts as the central respiratory center

How medulla determines respiratory

Central and Peripheral Chemoreceptors, stretch receptors in the lungs, proprioceptors in muscles and joints

Major plasma proteins

Albumins, Globulins, and Fibrinogen

Albumins

Transport fatty acids, thyroid hormones, and steroids

Globulins

Immunoglobulins and transport globulins

Fibrinogen

Clot formation

Base

Broad, superior part of the heart where major vessels attach

Apex

The pointed, inferior portion of the heart

Heart wall layers

Endocardium, Myocardium (contracts), epicardium

Pericardium

Double-wall sac that encloses the heart

Parietal pericardium = outer layer; epicardium = inner layer

Pulmonary circuit

Carries blood between the heart and the lungs (right atrium --> left atrium)

Systemic circuit

Carries blood between the heart and the rest of the body (Left atrium --> right atrium)

AV node

Relays and intensifies the impulse from the SA node, introducing a slight delay to allow the atria to contract fully

Bundle of His/AV Bundle

Conducts the impulse from the AV node toward the ventricles

Purkinje fibers

Spread the impulse throughout the ventricular myocardium, causing the ventricles to contract

Sympathetic Influence

Releases catecholamines (epinephrine, norepinephrine)

Causes a positive chronotropic effect (increased heart rate)

Causes a positive inotropic effect (increased force of contraction)

Parasympathetic Influence

Releases acetylcholine

Causes a negative chronotropic effect

Causes a negative inotropic effect

Primarily via the vagus nerve

Capacitance vessels

systemic veins; hold most of the blood

Command center of the endocrine system

The hypothalamus and pituitary gland

Hypothalamus linking nervous and endocrine system as an endocrine organ

Hypothalamic neurons produce antidiuretic hormone (ADH) and oxytocin (OXT). These hormones travel along axons to the posterior pituitary, where they are stored and released into the bloodstream. These are called neurosecretions

Hypothalamus linking nervous and endocrine system by secreting regulatory hormones

The hypothalamus produces releasing and inhibitory hormones that control the anterior pituitary. There, regulatory hormones travel via a specialized blood vessel network called the hypophyseal portal system to precisely regulate the anterior pituitary's hormone release

Hypothalamus linking nervous and endocrine system: containing autonomic centers

Autonomic centers in the hypothalamus exert nervous control over the adrenal medulla, influencing the release of epinephrine and norepinephrine

Thyroid Gland

Located anterior to the trachea

Produces Thyroxine (T4) and Triiodothyronine (T3) which regulates metabolic rate

Produces Calcitonin (CT) which lowers blood calcium levels by inhibiting osteoclast activity

Parathyroid Glands

Four small glands embedded on the posterior surface of the thyroid

Produce Parathyroid Hormone (PTH) which raises blood calcium levels by stimulating osteoclasts, reducing calcium loss in urine, and promoting calcium absorption in the intestines via vitamin D activation

Adrenal glands regions

Medulla and Cortex

Adrenal Medulla

Part of the sympathetic nervous system

Produces epinephrine and norepinephrine

Adrenal Cortex

Produces cortisol, aldosterone (regulates blood pressure), and androgens (sex hormones)

Pancreatic islets

Performs the endocrine role of the pancreas

Pancreatic alpha cells

secrete glucagon: raises blood glucose levels

Pancreatic beta cells

Secrete insulin: lowers blood glucose levels

Pancreatic delta cells

Secrete somatostatin: inhabits the secretion of both glucagon and insulin, slowing nutrient absorption

Pancreatic PP Cells

Secrete pancreatic polypeptide, which inhibits gallbladder contractions and regulates some pancreatic enzymes

Heart

Produces Atrial Natriuretic Peptide (ANP) and Brain Natriuretic Peptide (BNP) in response to high blood pressure; inhibits ADH and aldosterone to lower blood pressure

Kidneys

Produce Erythropoietin (EPO) in response to low oxygen levels, which stimulates red blood cell production

Produces Renin, which raises blood pressure

Converts vitamin D into its active form calcitriol

Pineal Gland

Located in the epithalamus of the brain; produces melatonin

Adipose tissue

Produces leptin (appetite/fat storage) and resistin (insulin resistance)

System that remains relatively stable with age compared to other systems

Endocrine