BIO: bodily systems

Digestive System: Purpose

• Converts food into simpler molecules that can be used by cells, absorbs nutrients, eliminates waste

Digestive System: Process Duration

• The entire digestive process takes 24–33 hours

Mouth: Function

• First stop for food breakdown

Pharynx: Function

• Connects mouth to esophagus

Epiglottis: Function

• Flap that prevents food from entering the airway when swallowing

Esophagus: Function

• Muscular tube connecting the mouth to the stomach

Liver: Function

• Produces bile to help break down fats

Gall Bladder: Function

• Stores bile produced by the liver

Stomach: Function

• Muscular pouch where involuntary churning and chemical digestion occurs

Pancreas: Function

• Produces enzymes to break down carbohydrates, proteins, and fats

Small Intestine: Function

• Digestion completed here with help from liver and pancreas enzymes

Villi: Function

• Projections in small intestine lining that absorb nutrients

Large Intestine: Function

• Absorbs water and salts

Appendix: Function

• Tube-like extension off the large intestine

Rectum: Function

• Last part of the digestive system

Digestive System: Interactions with Other Systems

• Muscular: contains smooth muscle
• Nervous: controls digestion rate
• Circulatory: delivers nutrients to cells
• Endocrine: hormones like insulin control blood sugar

Excretory System: Purpose

• Eliminates waste products from the body

Kidneys: Function

• Filter blood to remove waste and maintain homeostasis

Nephron: Function

• Tiny filter that makes up the kidney

Ureters: Function

• Tubes connecting kidneys to the bladder

Urinary Bladder: Function

• Stores urine until elimination

Urethra: Function

• Tube that expels urine from the body

Excretory System: Other Organs

• Skin and lungs help eliminate waste

Excretory System: Interactions with Other Systems

• Circulatory: carries waste to kidneys
• Endocrine: hormones control water levels
• Respiratory: expels CO₂

Respiratory System: Purpose

• Provides oxygen for cellular respiration and removes carbon dioxide

Nose & Mouth: Function

• Entry points for air during respiration

Pharynx: Function

• Connects nose/mouth to larynx

Larynx: Function

• Houses vocal cords

Trachea: Function

• Passes air from larynx to bronchi

Bronchi: Function

• Passes air from trachea to lungs

Bronchioles: Function

• Branches of bronchi within lungs

Alveoli: Function

• Sacs where O₂ and CO₂ are exchanged

Diaphragm: Function

• Muscle that enables breathing

Respiratory System: Interactions with Other Systems

• Circulatory: delivers O₂ to cells, removes CO₂
• Excretory: eliminates toxic CO₂

Circulatory System: Purpose

• Transports oxygen, nutrients, hormones

Heart: Function

• Pumps blood throughout the body

Blood Vessels: Function

• Arteries carry blood away from heart

Blood: Components

• Red Blood Cells: carry O₂
• White Blood Cells: fight infection
• Platelets: aid clotting
• Plasma: fluid portion

Circulatory System: Interactions with Other Systems

• Connected to almost all systems to deliver oxygen and nutrients

Skeletal System: Purpose

• Supports body, protects organs, allows movement, stores minerals, produces blood cells

Bones: Function

• Support and protection
• Red marrow: produces blood cells
• Yellow marrow: stores fat

Joints: Function

• Points where bones meet for movement

Cartilage: Function

• Cushions ends of bones to prevent grinding

Ligaments: Function

• Connect bones to other bones

Tendons: Function

• Connect muscles to bones

Skeletal System: Interactions with Other Systems

• Muscular: bones and muscles enable movement
• Circulatory/Immune: blood cells produced in marrow

Muscular System: Purpose

• Produces voluntary movement, circulates blood, moves food through digestive system

Cardiac Muscle: Function

• Makes up heart

Skeletal Muscle: Function

• Voluntary movement of bones

Smooth Muscle: Function

• Involuntary movement

Muscular System: Interactions with Other Systems

• Works with skeletal (movement), circulatory (O₂/waste transport), nervous (controls contractions)

Nervous System: Purpose

• Recognizes and coordinates the body’s response to internal and external changes

Neurons: Function

• Basic unit of structure and function of the nervous system

Neuron: Parts

• Cell body: main part of neuron
• Dendrites: receive impulses and deliver them to cell body
• Axon: carries impulses away from cell body

Brain: Function

• Control center of the body

Spinal Cord: Function

• Transmits signals between brain and body

Central Nervous System (CNS)

• Brain + spinal cord

Peripheral Nervous System (PNS)

• Nerves that carry messages to/from CNS

Nervous System: Interactions with Other Systems

• Works closely with muscular and digestive systems

Integumentary System: Purpose

• Barrier against infection/injury, regulates temperature, protects from UV radiation

Skin: Layers

• Epidermis: outer layer, covers body
• Dermis: inner layer, contains blood vessels, nerves, hair follicles, sweat/oil glands

Hair, Skin, Nails: Composition

• Made of keratin

Pigment: Function

• Controlled by melanin

Sweat Glands: Function

• Help maintain homeostasis

Oil Glands: Function

• Lubricate skin and hair

Integumentary System: Interactions with Other Systems

• Contains blood vessels and nerves

Immune System: Purpose

• Protects the body from disease

Immune System: Organs/Components

• White Blood Cells, Thymus, Spleen, Lymph Vessels, Lymph Nodes

Immune System: Interactions with Other Systems

• Works closely with circulatory system

Endocrine System: Purpose

• Controls growth, development, metabolism

Hypothalamus: Function

• Link between endocrine and nervous systems

Pituitary Gland: Function

• Main gland

Thyroid: Function

• Produces thyroxin (growth/metabolism hormone)

Parathyroid: Function

• Produces PTH

Adrenal Glands: Function

• Release hormones for stress (epinephrine/adrenaline, norepinephrine)

Pancreas: Function

• Produces insulin and glucagon

Ovaries: Function

• Secrete female sex hormones

Testes: Function

• Secrete male sex hormones

Endocrine System: Interactions with Other Systems

• Works closely with reproductive and digestive systems

Reproductive System: Purpose

• Produces reproductive cells

Male Reproductive Organs: Penis

• Transports sperm out of male body

Male Reproductive Organs: Testes

• Site of sperm production

Male Reproductive Organs: Epididymis

• Where sperm mature

Male Reproductive Organs: Vas Deferens

• Stores mature sperm before transport to urethra

Female Reproductive Organs: Ovaries

• Where eggs mature

Female Reproductive Organs: Fallopian Tubes

• Connect ovaries to uterus

Female Reproductive Organs: Uterus

• Where fetus develops during pregnancy

Female Reproductive Organs: Vagina

• Canal leading to uterus

Reproductive System: Interactions with Other Systems

• Works closely with endocrine system (hormonal regulation)
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