What are the four major types of tissues?
Epithelial, Connective, Muscle, Nervous
What do Epithelial tissues do?
- cover organs, and lines hollow organs
- forms the inner linings of body cavities
What do connective tissues do?
- provide support + protection
- can repair tissue damage
- work as frameworks
What are the types of Connective Tissue Fibers?
Ligaments, tendons, Elastic fibers, and reticular fibers
What do ligaments do?
connect bones to bones
What do tendons do?
connect muscle to bone
What do elastic fibers do?
provides support to other bones, found in arteries and lungs
What do reticular fibers do?
surronds and supports organs, mesh like pattern of tissue
What do muscle tissues do?
produce movement of the body parts
What do nervous tissues do?
coordinating and controlling many body activities, found in brain and spinal cord
What is the integemntary system?
the skin
What are the functions of the skin?
- Provides protective covering
- Helps regulate body temp
- Prevents excessive water loss
- Houses sensory receptors
- Excretes waste
What are the two layers of the skin?
Dermis and Epidermis
What is the epidermis?
- The outer layer of the skin.
- Lacks blood vessels
- The further towards the surface a cell gets the older it is
- The older outer cells harden in a process called keratinization
What is keratinization?
- Cytoplasm of the cell hardens and fills with water tight keratin
- Results in many layers of tightly packed dead cells
- This layer is called the stratum corneum
What is melanin?
- Produced by cells located in the Epidermis called Melanocytes
- Melanin is a dark pigment that provides skin color
- Absorbs ultraviolet radiation to prevent mutations in DNA of skin cells
What is the dermis?
- Binds the epidermis to the underlying tissues
- Largely made up of dense connective tissue
- Contain blood vessels that provide nutrients to all skin cells
- Contains hair follicles, sweat glands, and sebaceous glands
What are the accessory structures of the skin?
- Nails
- Hair Follicles
- Sweat Glands
Nails
- Protective coverings of the ends of the fingers and toes
Consists of: - A nail plate: the nail itself
- A nail bed: the skin under the nail
- Lunula: The white semicircle at the base of your nail (the newest hair cells)
Hair follicles
- A group of epidermal cells at the base of a tubelike depression
- Nourished by dermal blood flow
- Older cells get pushed further and further out until they are keratinized
What is the Arrector Pili Muscle?
A small muscle fiber responsible for making the hair stand straight up when cold or upset.
Sebaceous Glands
- Glands that are typically associated with hair follicles
- They secrete an oily mixture of fatty material and cellular debris called sebum
- Sebum is secreted through small ducts into the hair follicles
- Keeps skin soft and waterproof ( AKA the oils in our hair)
types of Sweat glands
Eccrine and Apocrine
Eccrine Glands
- Respond to temperature changes due to weather or physical activity
- Most are found on the neck, back, and forehead
- Produce sweat
- Ducts open straight to the skin aka pours
