What are the four types of tissues?
- Epithelial (covering)
- Muscle (movement)
- Nervous (control)
- Connective (support)
These tissues serve distinct functions in the body.
How is epithelial tissue classified?
According to the number of cell layers and their shape
Epithelial tissue is avascular, meaning it lacks blood vessels.
Give examples of epithelial tissue types.
- Simple cuboidal
- Stratified squamous
- Simple columnar
- Pseudostratified, ciliated columnar
These examples illustrate various shapes and arrangements of epithelial cells.
What is connective tissue primarily responsible for?
- Binding and support
- Protection against infection
- Tissue repair
- Insulation
Connective tissue is the most abundant tissue by weight and is usually well vascularized.
What makes up the extracellular matrix (ECM) in connective tissue?
Ground substance + protein fibers
The three types of protein fibers are collagen, elastin, and reticular.
List the classes of connective tissue.
- Connective tissue proper
- Cartilage
- Bone
- Blood & Lymph
Each class has different functions and structural characteristics.
What are the two layers of the integumentary system?
- Epidermis
- Dermis
The integumentary system includes skin and accessory organs.
What is the predominant cell type in the epidermis?
Keratinocytes
Keratinocytes produce keratin, which protects against various environmental factors.
What is the function of melanocytes in the epidermis?
Produce melanin
Melanin provides protection from UV radiation and contributes to hair color and skin tone.
What are the five layers (strata) of the epidermis?
- Stratum corneum
- Stratum lucidum
- Stratum granulosum
- Stratum spinosum
- Stratum basale
Each layer has distinct characteristics and functions.
What are epidermal ridges and their purpose?
Elevations in a pattern on the palmar and plantar surfaces
They increase surface area for grip and give rise to fingerprints.
What three pigments contribute to skin tone?
- Melanin
- Carotene
- Hemoglobin
The expression of these pigments varies among individuals.
What are common risk factors for skin cancer?
- Skin type
- Sun exposure
- Family history
- Age
- Immunologic status
Melanomas can metastasize quickly and are a serious health concern.
What are the two regions of the dermis?
- Papillary region
- Reticular region
The dermis contains collagen and elastic fibers that provide support for the skin.
Name the types of skin glands.
- Sebaceous (oils)
- Apocrine (milky)
- Eccrine (clear)
- Ceruminous (waxy)
These glands are regulated by the sympathetic nervous system.
What are the six functions of the skin?
- Thermoregulation
- Blood reservoir
- Protection from the environment
- Cutaneous sensations
- Excretion and absorption
- Synthesis of vitamin D
Each function is vital for maintaining homeostasis.
How does the skin contribute to thermoregulation?
By dilating or constricting blood vessels and promoting sweat production
This helps maintain a body temperature of 37°C.
What role does melanin play in skin protection?
Protects stem cells from damaging UV rays
Melanin is crucial for reducing the risk of skin damage and cancer.
What is the process for the synthesis of Vitamin D?
Requires UV exposure and involves the liver and kidney for further metabolism
Vitamin D is important for calcium homeostasis.
