Skin and Membranes Flashcards
What are the two classifications of body membranes?
- Epithelial membranes - composed of epithelial tissue and an underlying layer of connective tissue
- Connective tissue membranes - composed largely of various types of connective tissue
What are the three types of epithelial membranes?
- Cutaneous membrane - the skin
- Serous membranes - simple squamous epithelium on a connective tissue basement membrane
- Mucous membranes - line body surfaces that open directly to the exterior; produce mucus, a thick secretion that keeps the membranes soft and moist
What are the two layers of serous membranes?
Parietal - lines walls of body cavity
Visceral - covers organs within body cavity
What is the pericardium?
Parietal and visceral layers line a fibrous sac around the heart and a visceral layer covers the heart wall
What is the pleura?
Parietal and visceral layers line the walls of the thoracic cavity and cover the lungs.
What is the peritoneum?
Parietal and visceral layers line walls of abdominal cavity and cover the organs in that cavity.
What is pleurisy?
Inflammation of the serous membranes that line the chest cavity and cover the lungs.
What is peritonitis?
Inflammation of the peritoneum - serous membranes in the abdominal cavity that line the walls and cover the abdominal organs.
Describe connective tissue membranes.
- Do not contain epithelial components
- produce a lubricant called synovial fluid
- examples are the synovial membranes lining the joint capsules that surround and attach the ends of articulating bones in moveable joints and in the lining of bursal sacs
What are the two primary layers of the skin?
- Epidermis - outermost and thinnest primary layer of skin
- Dermis - deeper and thicker of layer composed largely of connective tissue
Describe the layers of the epidermis.
- Stratum germinativum - deepest layer of cells that continuously reproduce, and new cells move toward the surface
- Stratum corneum - outermost layer of keratin filled cells
What is keratin?
A tough, waterproof protein that makes up the stratum corneum.
Where can you find pigment-producing melanocyte cells?
In the basal layer of the stratum germinativum.
What is cyanosis?
Bluish colour of skin indicates decreased blood oxygen level.
Describe the dermal-epidermal junction.
- glue-like layer between the dermis and epidermis
- small bumps called dermal papillae help stabilize the junction
Describe the dermis.
- deeper and thicker layer of the two primary skin layers
- upper layer characterized by parallel rows of tiny bumps called dermal papillae
- ridges and grooves form fingerprints
- deeper reticular layer filled with collagen
- contains nerve endings, muscle fibers, hair follicles, sweat and sebaceous glands, and many blood vessels
Describe subcutaneous tissue.
- also called the superficial fascia or hypodermis
- located deep to the dermis but is not part of the skin
- loose fibrous and adipose (fat) tissue are prominent in this layer
What is lanugo?
Soft hair of a fetus and newborn.
What is the arrector pili?
Smooth muscle of the skin that produces ‘goose bumps’ and causes hair to stand up straight.
What is the lunula?
White, crescent-shaped area of the nail.
What are eccrine glands?
Sweat glands; most numerous, important and widespread; produce perspiration; body heat regulation
What are apocrine glands?
- primarily in axilla and genitalia
- secretes thicker substance
- breakdown of secretion by skin bacteria produces odor
What are sebaceous glands?
- secrete oil of sebum for hair and skin
- secretion increases during adolescence
- regulated by sex hormones
-sebum by darken to form blackhead
What are the five functions of the skin?
- Protection - first line of defense against infection by microbes; UV rays from sun; harmful chemicals; cuts and tears
- Temperature regulation - regulation of sweat secretion; regulation of blood flow through blood vessels close to the body surface
- Sense organ activity - skin functions as an enormous sense organ; receptors serve as receivers for the body, keeping it informed of changes in its environment
- Excretion - sweat can rid the body of ions and wastes
- Synthesis of vitamin D
