Lillys notes

🧬 Chapter 5 — Tissues & Body Systems

1. Organs

Organ: 2+ types of tissues working together to perform a specific function.

Examples: heart, brain, stomach, liver, kidneys

Vital organs: necessary for life (heart, brain, lungs, etc.).

Some organs can be removed without causing death, such as the appendix, spleen, and gallbladder.

Kidneys: one can often be removed and the other can continue functioning.

🧪 Bioprinting Artificial Tissues

Uses 3D printing to create tissues.

May eventually help replace damaged tissues/organs.

Scientists are working on growing cells in labs and creating functional tissues.

⸻

2. Body Systems

Body system: organs working together to perform complex functions.

Systems are interconnected and depend on one another.

A problem in one system can affect other systems.

⸻

🦴 3. Skeletal System

Main functions

Support the body

Protect soft organs

Provides structure for movement

Stores minerals such as calcium and phosphorus

Bone marrow produces blood cells

Main components

Bones

Joints

Ligaments

Cartilage

Two divisions

Axial skeleton (80 bones)

Skull

Vertebrae

Ribs

Sternum

Protects brain, spinal cord, and organs of the chest

Appendicular skeleton (126 bones)

Arms and legs

Supporting bones of the limbs

Helps position and move the limbs

Total skeletal system = 206 bones

⸻

💪 4. Muscular System

Main functions

Produces movement

Maintains body position

Produces heat

Controls openings of the digestive tract

Supports/protects soft tissues

3 types of muscle

Skeletal: voluntary; moves the skeleton

Smooth: involuntary; found in organs

Cardiac: involuntary; found only in the heart

⸻

🧴 5. Integumentary System

Main functions

Protection from injury and infection

Helps regulate body temperature

Provides sensation

Helps prevent water loss

Main structures

Skin

Epidermis: outer layer; protects underlying tissues

Dermis: provides strength and contains glands

Hair follicles → produce hair

Hair →

Provides sensation

Protects the head

Sebaceous glands →

Produce oil that lubricates skin/hair

Sweat glands →

Produce sweat for cooling

Nails →

Protect and stiffen fingertips/toes

Sensory receptors →

Detect touch, pressure, temperature, and pain

⸻

🧪 6. Endocrine System

Main function

Acts as a control system using hormones.

Regulates:

Growth

Metabolism

Fluid/electrolyte balance

Stress responses

Reproduction

Major glands & functions

Pituitary: controls other glands; regulates growth/fluid balance

Thyroid: controls metabolic rate and calcium levels

Parathyroid: regulates calcium

Thymus: involved in white blood cell/immune maturation

Adrenal glands: water balance, metabolism, cardiovascular/respiratory activity

Pancreas: regulates blood glucose

Testes: male reproductive functions

Ovaries: female reproductive functions

⸻

🧠 7. Nervous System

Main function

Receives and processes information.

Controls and coordinates body activities.

Helps the body respond to internal and external changes.

Central Nervous System (CNS)

Brain

Processes complex information

Controls voluntary activities

Spinal cord

Carries information to/from the brain

Controls many simple involuntary activities

Peripheral Nervous System (PNS)

Peripheral nerves

Connects the CNS with the rest of the body and sensory organs.

Key structures

Nerve cells (neurons) → transmit signals

Ganglion → group of nerve cell bodies outside the CNS

Axons → carry nerve signals

⸻

❤️ 8. Cardiovascular System

Main function

Circulates blood throughout the body.

Delivers oxygen and nutrients.

Removes waste products.

Main components

Heart

Pumps blood

Maintains blood pressure

Blood vessels

Carry/distribute blood throughout the body

Arteries

Carry blood away from the heart

Lead toward capillaries

Capillaries

Main site of exchange between blood and surrounding/interstitial fluid

Veins

Return blood to the heart

Blood

Transports oxygen and carbon dioxide

Delivers nutrients

Removes waste

Helps defend against infection

⸻

🫁 9. Respiratory System

Main functions

Brings oxygen into the body.

Removes carbon dioxide from cellular metabolism.

Filters, warms, and moistens inhaled air.

Helps maintain blood acid-base balance.

Helps eliminate alcohol.

Main structures

Nasal cavities → Pharynx → Larynx → Trachea → Bronchi → Lungs → Alveoli

Alveoli

Tiny air sacs

Main site of gas exchange between air and blood

⸻

🛡️ 10. Lymphatic & Immune System

Main functions

Maintains proper fluid balance

Helps protect the body from infection

Returns excess fluid to the bloodstream

Important structures

Lymph

Lymph vessels

Lymph nodes

Thymus

Spleen

Tonsils

Lymph nodes

Filter lymph

Help capture unwanted/infectious agents

Lymphocytes

Specialized white blood cells that fight infection.

⸻

🍎 11. Gastrointestinal (Digestive) System

Main functions

Breaks down food mechanically and chemically.

Absorbs usable nutrients.

Moves unused material out of the body.

Main organs

Mouth

Pharynx

Esophagus

Stomach

Small intestine

Colon

Liver

Gallbladder

Pancreas

Anus

Basic pathway

Mouth → Pharynx → Esophagus → Stomach → Small intestine → Colon → Anus

⸻

🚽 12. Urinary System

Main function

Removes waste from the blood.

Helps regulate fluid and chemical balance.

Main organs

Kidneys: filter blood and produce urine

Ureters: carry urine to bladder

Bladder: stores urine

Urethra: carries urine out of body

Pathway

Kidneys → Ureters → Bladder → Urethra

⸻

♀️♂️ 13. Reproductive System

Female

Ovaries: produce eggs and reproductive hormones

Uterus: supports pregnancy

Fallopian tubes: transport eggs

Vagina: passage connecting uterus to outside

Mammary glands: produce milk

Male

Testes: produce sperm and hormones

Prostate: contributes fluid to reproductive system

Urethra: carries urine and reproductive fluid out of body

⸻

🩸 14. Septicemia / Sepsis

Septicemia (sepsis): infection that is present in the blood and can spread throughout the body.

Can begin when bacteria enter the bloodstream, such as from an infection or injury.

Can affect multiple organs.

Severe cases can cause organ dysfunction/failure.

Possible signs

Fever

Chills

Fast heart rate

Skin changes

Low oxygen

Changes in mental status

⸻

⭐ Super Important Connections

Know these for a test:

4 tissue types

Epithelial • Connective • Muscle • Nervous

4 major body systems from these pages

Skeletal → support/protection

Muscular → movement/heat

Nervous → control/signals

Cardiovascular → transport

Blood flow basics

Heart → Arteries → Capillaries → Veins → Heart

Urinary pathway

Kidneys → Ureters → Bladder → Urethra

Respiratory pathway

Nasal cavity → Pharynx → Larynx → Trachea → Bronchi → Lungs → Alveoli

Skeletal

Axial = 80

Appendicular = 126

Total = 206

Muscle

Skeletal = voluntary

Smooth = involuntary

Cardiac = involuntary + heart only