TEAS Anatomy and Physiology Review: Body Systems Made Simple

Human Anatomy and Physiology makes up approximately 64% of the TEAS Science section—that's about 32 questions! Understanding body systems is essential not just for the test, but for your nursing career. This guide breaks down each system into easy-to-understand concepts.

The Cardiovascular System

The cardiovascular system transports blood, oxygen, nutrients, and waste products throughout the body. It's one of the most heavily tested systems on the TEAS.

Heart Anatomy

• Four chambers: Right atrium, Right ventricle, Left atrium, Left ventricle
• Four valves: Tricuspid (right AV), Pulmonary, Mitral/Bicuspid (left AV), Aortic
• Septum: Wall dividing left and right sides
• Pericardium: Protective sac around the heart

Blood Flow Pathway (MUST KNOW!)

Follow the blood through the heart:

• Deoxygenated blood enters RIGHT ATRIUM via superior/inferior vena cava
• Through tricuspid valve to RIGHT VENTRICLE
• Through pulmonary valve to PULMONARY ARTERIES → LUNGS
• Oxygenated blood returns via PULMONARY VEINS to LEFT ATRIUM
• Through mitral valve to LEFT VENTRICLE
• Through aortic valve to AORTA → BODY

Cardiac Conduction System

• SA Node (Sinoatrial): The natural pacemaker, located in right atrium
• AV Node (Atrioventricular): Delays signal, located between atria and ventricles
• Bundle of His: Transmits impulse to ventricles
• Purkinje Fibers: Distribute impulse throughout ventricles

Blood Vessels

• Arteries: Carry blood AWAY from heart (thick, muscular walls, high pressure)
• Veins: Carry blood TOWARD heart (thinner walls, valves to prevent backflow)
• Capillaries: Tiny vessels where gas/nutrient exchange occurs
• Exception: Pulmonary arteries carry deoxygenated blood; pulmonary veins carry oxygenated blood

Blood Components

• Red Blood Cells (RBCs): Carry oxygen via hemoglobin
• White Blood Cells (WBCs): Fight infection (immune defense)
• Platelets: Blood clotting
• Plasma: Liquid portion (55% of blood volume)

The Respiratory System

The respiratory system brings oxygen into the body and removes carbon dioxide.

Upper Respiratory Tract

• Nose/Nasal cavity: Filters, warms, and humidifies air
• Pharynx (throat): Passageway for air and food
• Larynx (voice box): Contains vocal cords, prevents food from entering airway

Lower Respiratory Tract

• Trachea (windpipe): Tube leading to lungs, lined with cilia
• Bronchi: Two branches (right and left) entering each lung
• Bronchioles: Smaller branches within lungs
• Alveoli: Tiny air sacs where gas exchange occurs

Mechanics of Breathing

• Inhalation: Diaphragm contracts and moves DOWN, rib cage expands, air rushes IN
• Exhalation: Diaphragm relaxes and moves UP, rib cage contracts, air is pushed OUT
• This is controlled by the medulla oblongata in the brainstem

Gas Exchange

• Occurs in alveoli (millions of tiny sacs)
• Oxygen diffuses from alveoli INTO blood
• Carbon dioxide diffuses from blood INTO alveoli (to be exhaled)
• Driven by concentration gradients (high to low)

The Digestive System

The digestive system breaks down food into nutrients that can be absorbed and used by the body.

The Digestive Pathway

• Mouth: Mechanical digestion (chewing), chemical digestion begins (salivary amylase breaks down starches)
• Esophagus: Moves food to stomach via peristalsis (wave-like contractions)
• Stomach: Churns food, releases HCl acid and pepsin (breaks down proteins)
• Small Intestine: PRIMARY site of nutrient absorption (villi increase surface area)
• Large Intestine (Colon): Absorbs water, forms and stores feces
• Rectum/Anus: Elimination of waste

Accessory Organs

• Liver: Produces bile (breaks down fats), detoxifies blood, stores glycogen
• Gallbladder: Stores and concentrates bile
• Pancreas: Produces digestive enzymes (amylase, lipase, protease) and insulin

Key Digestive Enzymes

• Amylase: Breaks down carbohydrates/starches (mouth and pancreas)
• Pepsin: Breaks down proteins (stomach)
• Lipase: Breaks down fats/lipids (pancreas)
• Bile: Emulsifies fats (makes them easier to digest, produced by liver)

The Nervous System

The nervous system controls all body functions through electrical signals.

Central Nervous System (CNS)

• Brain: Control center for thinking, memory, emotions, movement
• Spinal Cord: Connects brain to body, handles reflexes

Peripheral Nervous System (PNS)

• Somatic: Voluntary control (moving your arm)
• Autonomic: Involuntary control (heart rate, digestion)

Autonomic Divisions

• Sympathetic: 'Fight or Flight' - increases heart rate, dilates pupils, releases adrenaline
• Parasympathetic: 'Rest and Digest' - slows heart rate, promotes digestion, conserves energy

Neuron Structure

• Dendrites: Receive signals from other neurons
• Cell Body: Contains nucleus, processes information
• Axon: Transmits signals away from cell body
• Synapse: Gap between neurons where neurotransmitters are released
• Myelin Sheath: Insulation that speeds up signal transmission

Brain Regions

• Cerebrum: Largest part, thinking, memory, voluntary movement
• Cerebellum: Coordination, balance, fine motor control
• Brainstem: Basic life functions (breathing, heart rate, consciousness)
• Hypothalamus: Regulates temperature, hunger, thirst, hormones
• Medulla Oblongata: Controls breathing, heart rate, blood pressure

The Urinary System

The urinary system filters blood and removes waste as urine.

Key Structures

• Kidneys: Filter blood, produce urine, maintain electrolyte balance
• Nephron: Functional unit of kidney (where filtration occurs)
• Ureters: Tubes carrying urine from kidneys to bladder
• Bladder: Stores urine
• Urethra: Tube carrying urine out of body

Urine Formation

• Filtration: Blood is filtered in glomerulus (removes waste, keeps blood cells)
• Reabsorption: Useful substances (water, glucose, salts) are returned to blood
• Secretion: Additional waste products are added to urine
• Excretion: Urine is expelled from the body

The Musculoskeletal System

Types of Muscle

• Skeletal: Voluntary, attached to bones, striated appearance
• Cardiac: Involuntary, only in heart, striated
• Smooth: Involuntary, in organs and blood vessels, non-striated

Bone Types

• Long bones: Arms, legs (femur, humerus)
• Short bones: Wrists, ankles
• Flat bones: Skull, ribs, sternum
• Irregular bones: Vertebrae, facial bones

Joint Types

• Ball and Socket: Wide range of motion (shoulder, hip)
• Hinge: Back and forth motion (elbow, knee)
• Pivot: Rotation (neck, forearm)
• Gliding: Sliding motion (wrists, ankles)

The Endocrine System

The endocrine system uses hormones to regulate body functions.

Major Glands and Hormones

• Pituitary: 'Master gland' - growth hormone, controls other glands
• Thyroid: Thyroxine - metabolism regulation
• Pancreas: Insulin (lowers blood sugar), Glucagon (raises blood sugar)
• Adrenal: Adrenaline (fight or flight), Cortisol (stress response)
• Ovaries/Testes: Estrogen, Progesterone, Testosterone - reproduction

Quick Review: Must-Know Facts

• Blood flows: Right atrium → Right ventricle → Lungs → Left atrium → Left ventricle → Body
• SA node is the heart's pacemaker
• Arteries carry blood AWAY from heart
• Alveoli are where gas exchange occurs
• Small intestine is the primary site of nutrient absorption
• Nephron is the functional unit of the kidney
• Neuron is the basic unit of the nervous system
• Sympathetic = 'Fight or Flight'; Parasympathetic = 'Rest and Digest'

Understanding these body systems is crucial for both the TEAS and your nursing career. Review this guide regularly, and you'll be well-prepared for the Science section!