Cavities, skin and homeostasis

Define the term ‘tissue’

A group of cells with similar structure that function together as a unit

What are body cavities?

Hollow area in the body to hold organs etc

What are the 2 types of cavities with examples of each?

Anterior cavity - thoracic cavity and abdominal cavity

Posterior cavity - cranial and spinal cavity

What are the 4 tissue membranes and their functions?

Serous membranes - line and lubricates internal body cavities by producing serous fluid, reduces friction between organs.

Mucous membranes - line airways, digestive tract, lubricates surface and captures debris

Synovial membrane - line spaces in movable joints

Cutaneous membrane - Form outer covering (skin)

What does the integumentary system include and its function?

Skin, nails, hair, glands. It regulates temp, serves as defense against micro-organisms, makes vit D, provides sensation, protects from injury and dehydration.

What is the epidermis?

Outer layer of skin, has no blood vessels. Contains 2 major cell types - keratinocytes which provide a tough waterproof protein. Melanocytes which provide dark pigment.

What is the dermis?

2nd layer of skin, supports tissues. Has fibers which provide strength and elasticity, collagen. Cells include fibroblasts, mast cells, white blood cells and fat cells.

What are the accessory structures of the dermis?

Hair - shaft above skin surface

Smooth muscle - attached to hair follicle, raises hair to upright position

Sebaceous glands - secrets sebum which moistens and softens skin

Sweat glands - secretes sweat to help in temp regulation

Blood vessels - supply nutrients, remove waste, assist in temp regulation

Sensory nerve endings - detect heat, cold, touch, pressure and vibration

What is homeostasis?

Maintenance of constant conditions of the internal environment regardless of external environment.

What is negative feedback?

Deviations from normal are detected and counteracted.

What are the components of negative feedback system?

Controlled variable - Any physical or chemical property that might vary and must be controlled

Sensor/Receptor - Monitors current value for controlled variable and sends info to control center

Control center - Receives input from sensor and signals effector

Effector - takes action to correct the imbalance

Give an example relating to body temp

Controlled variable: body temp

Sensors: temp sensory in skin and organs

Control center: Hypothalamus

Effectors: blood vessels, sweat glands, skeletal muscles