Anatomy & Physiology Study Guide: Cardiovascular, Respiratory, Urinary, Reproductive, Blood, and Lymphatic Systems

Respiratory System

Overview of the Respiratory System

The respiratory system is responsible for gas exchange, supplying oxygen to the blood and removing carbon dioxide. It consists of organs and structures that facilitate breathing and protect the body from airborne pathogens.

• Organs: Nose, nasal cavity, pharynx, larynx, trachea, bronchi, lungs, alveoli.

• Function: Each organ plays a role in filtering, warming, moistening air, conducting air, and gas exchange.

Conducting vs. Respiratory Zones

• Conducting Zone: Includes structures that transport air (nose to terminal bronchioles); no gas exchange occurs.

• Respiratory Zone: Includes respiratory bronchioles, alveolar ducts, and alveoli; site of gas exchange.

Histology of the Respiratory Tract

• Epithelium: Changes from pseudostratified ciliated columnar (upper tract) to simple squamous (alveoli) for efficient gas exchange.

• Connective Tissue: Supports and protects airways.

• Muscle Tissue: Smooth muscle regulates airway diameter.

• Hyaline Cartilage: Found in trachea and bronchi to maintain airway patency.

Nasal Cavity

• Structure: Divided by nasal septum; lined with mucosa.

• Function: Filters, warms, and moistens incoming air.

Pharynx

• Regions: Nasopharynx, oropharynx, laryngopharynx.

• Function: Passageway for air and food; participates in immune defense.

Larynx

• Structure: Cartilaginous; contains vocal cords.

• Function: Air passage, voice production.

Trachea and Bronchial Tree

• Trachea: Tube supported by cartilage rings; conducts air to bronchi.

• Bronchial Tree: Branches into bronchi and bronchioles; conducting and respiratory zones distinguished by presence of cartilage and smooth muscle.

• Bronchoconstriction/Bronchodilation: Smooth muscle contraction/relaxation affects airflow.

Alveolar-Capillary Membrane

• Histology: Simple squamous epithelium for gas exchange.

• Surfactant: Reduces surface tension, preventing alveolar collapse.

Lung Cavities and Membranes

• Body Cavity: Lungs are in the thoracic cavity.

• Membranes: Visceral and parietal pleura; pleural cavity contains lubricating fluid.

Mechanics of Breathing

• Inspiration: Diaphragm and external intercostals contract, increasing thoracic volume.

• Expiration: Passive during quiet breathing; forced expiration uses internal intercostals and abdominal muscles.

Regulation of Respiration

• Brainstem Structures: Medullary respiratory center and pontine respiratory group regulate breathing rhythm.

Effects of Cigarette Smoke

• Epithelium Changes: Ciliated epithelium replaced by stratified squamous; impairs mucociliary clearance.

• Consequences: Increased infection risk, chronic bronchitis, emphysema.

Urinary System

Overview of the Urinary System

The urinary system maintains homeostasis by filtering blood, removing waste, and regulating fluid and electrolyte balance.

• Structures: Kidneys, ureters, urinary bladder, urethra.

• Function: Each organ contributes to urine formation, storage, and elimination.

Kidney Anatomy

• External Anatomy: Renal capsule, adipose tissue, renal fascia protect and anchor kidneys.

• Internal Anatomy: Cortex (outer), medulla (inner), renal pyramids, renal pelvis.

Nephron Structure and Function

• Nephron: Functional unit; consists of glomerulus, Bowman’s capsule, proximal/distal tubules, loop of Henle, collecting duct.

• Glomerulus: Capillary network; site of filtration.

• Bowman’s Capsule: Surrounds glomerulus; collects filtrate.

Flow of Fluid and Blood

• Filtrate Path: Bowman’s capsule → proximal tubule → loop of Henle → distal tubule → collecting duct → renal pelvis → ureter → bladder → urethra.

• Blood Flow: Renal artery → afferent arteriole → glomerulus → efferent arteriole → peritubular capillaries → renal vein.

Macula Densa and Juxtaglomerular Cells

• Macula Densa: Detects sodium concentration; regulates filtration rate.

• Juxtaglomerular Cells: Secrete renin; regulate blood pressure.

Ureters, Bladder, and Urethra

• Ureters: Muscular tubes; transport urine from kidneys to bladder.

• Bladder: Muscular sac; stores urine.

• Urethra: Tube for urine excretion; shorter in females, longer in males.

• Micturition Reflex: Controls urination; involves detrusor muscle and sphincters.

• Urethral Sphincters: Internal (smooth muscle, involuntary), external (skeletal muscle, voluntary).

Reproductive System

Male Reproductive System

• Sex vs. Gender: Sex is biological; gender is social/psychological.

• Scrotum and Testes Descent: Gubernaculum guides testes; cremaster muscle regulates temperature.

• Testes: Produce sperm and testosterone; interstitial cells secrete hormones.

• Blood-Testes Barrier: Protects developing sperm from immune system.

• Spermatogenesis: Formation of sperm; occurs in seminiferous tubules.

• Sperm Structure: Acrosome (enzymes), mitochondria (energy), flagellum (motility).

• Duct System: Seminiferous tubules → epididymis → vas deferens → ejaculatory duct → urethra.

• Accessory Glands: Seminal vesicles, prostate, bulbourethral glands; secrete fluids for sperm viability.

• Semen: Mixture of sperm and glandular secretions; nourishes and protects sperm.

• Penis: Contains erectile tissue (corpora cavernosa, corpus spongiosum); glans and prepuce.

Female Reproductive System

• Ovaries: Produce oocytes and hormones.

• Oogenesis: Formation of ova; involves oogonia, oocytes, polar bodies, ovum.

• Uterine Tubes: Transport oocytes; fertilization occurs here.

• Uterus: Site of implantation and fetal development; three layers (endometrium, myometrium, perimetrium).

• Ligaments: Support uterus in pelvic cavity.

• Vagina: Muscular tube; receives penis, birth canal.

• External Genitalia: Vulva, labia, clitoris, prepuce; involved in protection and sexual function.

• Mammary Glands: Produce milk for infant nourishment.

Heart (Cardiovascular System)

Heart Anatomy and Membranes

• Body Cavity: Heart is in the mediastinum of the thoracic cavity.

• Membranes: Pericardium (fibrous and serous); pericardial cavity contains fluid.

Heart Wall Layers

• Layers: Epicardium (outer), myocardium (muscle), endocardium (inner), pericardium (covering).

• Function: Protection, contraction, lining chambers.

Cardiac vs. Skeletal Muscle

• Cardiac Muscle: Branched, intercalated discs, involuntary.

• Skeletal Muscle: Long, multinucleated, voluntary.

• Intercalated Discs: Allow rapid electrical communication.

Heart Chambers and Valves

• Chambers: Right/left atria, right/left ventricles.

• Valves: Tricuspid, pulmonary, mitral, aortic; prevent backflow.

• Myocardium Thickness: Left ventricle thicker due to higher pressure.

Major Vessels and Structures

• Arteries/Veins: Aorta, pulmonary arteries/veins, vena cava.

• Papillary Muscles/Chordae Tendineae: Prevent valve prolapse.

Cardiac Conduction System

• Components: SA node, AV node, AV bundle, bundle branches, Purkinje fibers.

Pulmonary vs. Systemic Circuits

• Pulmonary: Low pressure, oxygen-poor blood to lungs.

• Systemic: High pressure, oxygen-rich blood to body.

Coronary Circulation

• Function: Supplies heart muscle; blockage causes infarction.

Path of Blood Through the Heart

• Sequence: Right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary artery → lungs → pulmonary vein → left atrium → mitral valve → left ventricle → aortic valve → aorta.

Blood

Functions and Components of Blood

• Functions: Transport, regulation, protection.

• Components: Plasma (water, proteins), buffy coat (white blood cells, platelets), hematocrit (red blood cells).

Hemopoiesis

• Definition: Formation of blood cells from hemocytoblasts.

Red Blood Cells (Erythrocytes)

• Structure: Biconcave shape increases surface area.

• Hemoglobin: Protein binds oxygen; each molecule carries up to four O2.

• Oxygen Binding: $\mathrm{Hb} + \mathrm{O}_2 \rightarrow \mathrm{HbO}_2$

Erythropoiesis

• Definition: Production of erythrocytes; stimulated by erythropoietin.

Platelets and Hemostasis

• Origin: Fragments of megakaryocytes.

• Function: Clot formation; fibrin stabilizes clot.

• Hemostasis: $\text{Hemostasis} = \text{Vasoconstriction} + \text{Platelet Plug} + \text{Coagulation}$

White Blood Cells

• Types: Neutrophils, lymphocytes, monocytes, eosinophils, basophils.

• Function: Immune defense.

Antigens and Antibodies

• Location: Antigens on cell surfaces; antibodies in plasma.

Blood Vessel Structure and Circulation

Blood Vessel Wall Layers

• Layers: Tunica intima (inner), tunica media (muscle), tunica externa (outer).

Arteries vs. Veins

• Arteries: Thick tunica media, smaller lumen, higher pressure.

• Veins: Thinner walls, larger lumen, lower pressure, valves present.

Types of Arteries

• Elastic Arteries: Large, stretch to accommodate blood flow (e.g., aorta).

• Muscular Arteries: Distribute blood to organs.

Capillaries

• Types: Continuous (tight junctions), fenestrated (pores), sinusoids (large gaps).

• Function: Exchange of gases, nutrients, waste.

Capillary Beds and Precapillary Sphincters

• Structure: Network of capillaries; sphincters regulate flow.

Veins and Venous Return

• Structure: Valves prevent backflow; muscular activity aids return.

Hepatic Portal System

• Veins: Superior mesenteric, splenic, inferior mesenteric drain into portal vein.

• Function: Transports nutrients from GI tract to liver.

Fetal Circulation

• Functions: Oxygenation, nutrient delivery, waste removal, bypass of nonfunctional organs.

• Structures: Umbilical arteries/vein, placenta, foramen ovale, ductus arteriosus, ductus venosus, adult remnants.

Lymphatic System

Functions of the Lymphatic System

• Functions: Fluid balance, immune defense, absorption of fats.

Structures and Flow of Lymph

• Structures: Lymphatic vessels, lymph nodes, spleen, thymus, tonsils.

• Flow: Lymphatic capillaries → vessels → nodes → ducts → venous circulation.

• Prevention of Backflow: Valves in vessels.

Lymphatic Organs

Organ	Function
Lymph Nodes	Filter lymph, house immune cells
Spleen	Filters blood, recycles RBCs, immune response
Thymus	Maturation of T-cells
Tonsils	Protect against inhaled/ingested pathogens

Lymphocyte Production

• T-cells: Mature in thymus; cell-mediated immunity.

• B-cells: Mature in bone marrow; antibody-mediated immunity.

Additional info: Academic context and explanations were added to expand brief review points into full study notes. Tables and equations were formatted as required. These notes cover all listed topics for exam preparation in an anatomy and physiology college course.