Integration

Integumentary system

• Anatomy: Epidermis, Dermis, Sweat Glands, Sensory Receptors

• Key Roles:

• Shields muscles, bones, and organs from the environment.

• Packed with sensors – detects touch, pressure, pain, and temperature.

• Plays a leading role in cooling: sweating, vasodilation (expanding blood vessels near skin surface).

• Communicates constantly with the nervous system to adjust to external threats (heat, cold, injury).

Nervous system

• Anatomy: Central & Peripheral Nervous System

• Key Roles:

• Takes in signals from skin (heat, pressure, pain).

• Sends rapid-fire commands to muscles for movement (voluntary & reflex).

• Oversees automatic processes: heart rate, sweating.

• Directs the endocrine system via the hypothalamus (master regulator).

Endocrine System

• Anatomy: Glands all over the body, linked via blood.

• Key Roles:

• Releases hormones that shape muscle growth, metabolism, and stress responses.

• Controls bone strength via calcium regulation (parathyroid hormone, calcitonin).

• In stress, the HPA Axis (Hypothalamus-Pituitary-Adrenal) pumps out cortisol to support long-term balance.

• Fine-tunes energy output when muscles work hard or body temperature shifts.

Skeletal system

• Anatomy: 206 bones, flexible joints, shock-absorbing cartilage.

• Key Roles:

• Forms the framework – protects brain, heart, lungs.

• Acts as levers for muscle movement.

• Bone marrow inside produces blood cells (immunity, oxygen transport).

• Sensitive to mechanical stress (exercise) and hormonal control (e.g., growth hormone, vitamin D).

Muscular system

• Anatomy: Over 600 skeletal muscles, connected by tendons to bones.

• Key Roles:

• Moves bones & joints for action, reflexes.

• Contracts on nervous command – instantly or over time.

• Influenced by hormones for growth, repair, and metabolism.

• Produces heat – helps regulate body temperature, working with skin.

Integration scenarios - “ouch” moment

Example: You touch a hot stove 🔥

• Integumentary: Skin sensors scream "HOT!" → send signal to nerves.

• Nervous: Fast-track reflex arc → spinal cord commands muscle withdrawal.

• Muscles: Instantly contract, pulling your hand away.

• Endocrine: Adrenaline kicks in → heart races, body tenses, sweat starts.

Integration scenarios - thermoregulation

Example: Running on a sunny day 🏃☀

• Muscles: Work hard → generate lots of heat.

• Skin: Opens sweat glands, blood vessels widen (vasodilation) to release heat.

• Nervous System: Detects overheating → boosts sweat, reduces activity.

• Endocrine: Thyroid hormones adjust metabolism to balance heat production.

Integration scenarios - injury and repair

Example: You twist your ankle or break a bone 🦵⚡

• Skeletal: Bone structure is damaged – needs repair.

• Muscles: Limited movement, stiff, sore.

• Nervous: Sends pain signals, may trigger immobilization reflexes.

• Endocrine: Releases growth hormone and cortisol to heal tissue, manage inflammation.

• Integumentary: If the skin is wounded, it kicks off regeneration or scarring.