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Questions and Answers
What is the layer of the epidermis that is found only in thick skin?
What is the layer of the epidermis that is found only in thick skin?
Stratum Lucidum
What is the function of the papillary layer of the dermis?
What is the function of the papillary layer of the dermis?
To provide support for the epidermis and keep it in place
What is the main function of the sebaceous glands?
What is the main function of the sebaceous glands?
To produce sebum, an oily substance that keeps the skin from becoming dry and brittle
What is the name of the muscles attached to hair follicles in mammals?
What is the name of the muscles attached to hair follicles in mammals?
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What is the primary function of the stratum corneum?
What is the primary function of the stratum corneum?
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What is the name of the layer of the skin that separates the dermis and epidermis?
What is the name of the layer of the skin that separates the dermis and epidermis?
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What is the name of the glands that produce cerumen, or ear wax?
What is the name of the glands that produce cerumen, or ear wax?
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What is the primary function of the apocrine sweat glands?
What is the primary function of the apocrine sweat glands?
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What is the term for the time it takes for a keratinocyte to make its way to the surface of the skin and be sloughed off?
What is the term for the time it takes for a keratinocyte to make its way to the surface of the skin and be sloughed off?
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What is the term for the boundary between the dermis and hypodermis?
What is the term for the boundary between the dermis and hypodermis?
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What are the four main categories of tissues?
What are the four main categories of tissues?
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What is the main function of epithelial tissues?
What is the main function of epithelial tissues?
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What is the difference between simple and stratified epithelial tissues?
What is the difference between simple and stratified epithelial tissues?
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What is the role of the basement membrane in epithelial tissues?
What is the role of the basement membrane in epithelial tissues?
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What is the main characteristic of connective tissue?
What is the main characteristic of connective tissue?
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What are the five major classifications of connective tissue?
What are the five major classifications of connective tissue?
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What is the function of fibroblasts in fibrous connective tissue?
What is the function of fibroblasts in fibrous connective tissue?
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What is the difference between collagenous, reticular, and elastic fibers?
What is the difference between collagenous, reticular, and elastic fibers?
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What is the role of macrophages in connective tissue?
What is the role of macrophages in connective tissue?
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What is the function of adipocytes in connective tissue?
What is the function of adipocytes in connective tissue?
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What is the primary function of the serous membrane, and where is it typically found in the body?
What is the primary function of the serous membrane, and where is it typically found in the body?
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What is the main difference between the epithelial membrane and the endothelial membrane?
What is the main difference between the epithelial membrane and the endothelial membrane?
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What is the primary function of the synovial membrane, and where is it typically found in the body?
What is the primary function of the synovial membrane, and where is it typically found in the body?
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What is the main function of the endothelial membrane, and where is it typically found in the body?
What is the main function of the endothelial membrane, and where is it typically found in the body?
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What is the cutaneous membrane, and what are its main functions?
What is the cutaneous membrane, and what are its main functions?
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What is the main characteristic of the serous membrane that allows it to reduce friction between organs and cavity walls?
What is the main characteristic of the serous membrane that allows it to reduce friction between organs and cavity walls?
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What is the primary function of the epidermal membrane, and how does it differ from the dermal membrane?
What is the primary function of the epidermal membrane, and how does it differ from the dermal membrane?
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What is the main function of the synovial fluid produced by the synovial membrane?
What is the main function of the synovial fluid produced by the synovial membrane?
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What is the primary function of the endothelial membrane in the context of the cardiovascular system?
What is the primary function of the endothelial membrane in the context of the cardiovascular system?
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What is the main characteristic of the cutaneous membrane that allows it to regulate body temperature?
What is the main characteristic of the cutaneous membrane that allows it to regulate body temperature?
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Study Notes
Connective Tissue
- Ground substance: gelatinous, rubbery consistency, helps absorb compressive forces and protect cells
- Areolar tissue: loose arrangement of collagenous and elastic fibers, scattered cells, significant space between cells, lots of ground substance and blood vessels, found underlying epithelial tissue and surrounding blood vessels and nerves
- Functions: loosely binds epithelial tissue to its surface, provides blood and nutrients for epithelial tissue
- Reticular tissue: loose arrangement of reticular fibers, numerous lymphocytes and other blood cells, found in lymph nodes, spleen, and bone marrow
- Functions: supportive sponge-like network for lymphatic system, filters lymphatic fluid
- Dense Regular tissue: few cells, numerous collagen and elastic fibers, fibers occupy more space than cells or ground matrix, organized wavy pattern
- Functions: resists stress in one direction, found in ligaments and tendons
- Dense Irregular tissue: few cells, lots of collagen fibers, but fibers are not organized, found in dermis of the skin
- Functions: resists stress in multiple directions
Adipose Connective Tissue
- Consists primarily of closely packed adipocytes (fat cells) that store triglycerides
- Functions: provides energy, thermal insulation, and protective cushioning
- Found: at the base of the skin, in tissues of the breasts, and around some internal organs
Cartilage Connective Tissue
- Has a stiff, rubbery matrix, avascular, consists of chondrocytes (cartilage cells) in a rubbery matrix
- Three forms: Hyaline, Elastic, and Fibrocartilage
- Hyaline cartilage: fine collagen fibers, used at the end of bones to reduce friction, part of the trachea and larynx, makes up most of the fetal skeleton
- Elastic cartilage: has both elastin and collagen fibers, used in the external ear and the epiglottis in the throat
- Fibrocartilage: has coarse collagen fibers, used in areas that need more long-term durability due to stress
Bone Connective Tissue
- Contains osteocytes (bone cells) surrounded by a matrix that is strong and flexible
- Functions: supports softer tissues, provides leverage for muscles, protects some internal organs, stores minerals
- Makes up the bones (organs) of the skeleton
Blood Connective Tissue
- Has a liquid matrix that surrounds cells and cell-like structures (formed elements)
- Includes: WBC, RBC, and platelets
- Functions: transports substances, aids in protection from infection, found in the chambers of the heart and in the hollow lumens of the blood vessels
Nerve Tissue
- Used to transmit electrical signals within the body for communication
- Contains neurons and neuroglial cells
- Neurons: highly excitable cells that transmit signals
- Neuroglia: cells that support the neurons
- Found in the brain, spinal cord, and nerves
Muscle Tissue
- Used to cause movement
- Myocytes (muscle cells) are elongated and highly excitable
- Can contract (shorten) when excited, leading to movements of the body and/or movement of substances within the body
- Three types: Skeletal, Cardiac, and Smooth
Glands
- Cell or organs that secrete substances for use elsewhere in the body
- Types: Exocrine and Endocrine
- Exocrine glands: use tube-like structures called ducts to secrete or excrete their products to a nearby surface
- Endocrine glands: secrete their products into the bloodstream for transport to another cell
Membrane
- Flat sheet or layer made up of several tissues working closely together
- Types: Mucous, Serous, Synovial, Endothelium, and Cutaneous
- Mucous membrane: lines passages that open to the exterior of the body, functions: absorption, secretion, and protection
- Serous membrane: produces serous fluid, found on organs and lines/surrounds cavities, functions: reduces friction as organs move
- Synovial membrane: associated with joints, secretes synovial fluid, functions: protects and lubricates joints
- Endothelium: lines the vessels of the circulatory system, functions: allows for exchange of nutrients and gases
- Cutaneous membrane: commonly known as skin, consists of 2 layers: dermis and epidermis, functions: resistance to trauma and infection, barrier functions, vitamin D synthesis, sensation, thermoregulation, and nonverbal communication
Integumentary System
- Skin is the largest and heaviest organ, making up 15% of the body weight
- Functions: resistance to trauma and infection, barrier functions, vitamin D synthesis, sensation, thermoregulation, and nonverbal communication
- Structure: Epidermis, Dermis, and Hypodermis
- Epidermis: made up of stratified squamous epithelium, functions: physical and chemical protection, barrier against UV rays and chemicals
- Dermis: made up of connective tissue, functions: supports the epidermis, provides blood vessels and nerve endings
- Hypodermis: made up of connective tissue, functions: attaches the skin to underlying structures### Epidermis
- The epidermis is the outermost layer of the skin, consisting of 5 layers: Stratum basale, Stratum spinosum, Stratum granulosum, Stratum lucidum, and Stratum corneum.
- Keratinocytes, melanocytes, and tactile cells are found in the Stratum basale.
- The Stratum corneum is the most superficial layer, containing dead keratinocytes and keratin.
- It takes about 30-40 days for a keratinocyte to reach the surface and be sloughed off.
- The epidermis is avascular, with very few nerve supply through the tactile cells.
- It is highly mitotic, with the fastest reproducing cells in the body.
Dermis
- The dermis provides support for the epidermis and is much thicker than the epidermis.
- It is divided into two layers: papillary and reticular.
- The papillary layer is a thin layer near the dermal papillae, consisting of areolar loose connective tissue and abundant blood vessels.
- The reticular layer is a thick layer below the papillary layer, consisting of dense irregular connective tissue.
- The dermis contains associated structures such as glands, hair, and follicles.
Subcutaneous Membrane (Hypodermis)
- The subcutaneous membrane is a layer beneath the skin, binding skin to underlying tissue and structures.
- It is not as well defined as the boundary between the dermis and epidermis.
- It has more areolar and adipose tissue than the dermis.
- It is highly vascular and functions in padding the body, providing cushion and thermoregulation, and binding the skin to underlying tissue.
Accessory Organs
Hair (Pilus)
- Hair is found almost everywhere except for palms, soles, certain areas of fingers and toes, nipples, and parts of the genitals.
- It consists of the follicle, bulb, root, and shaft.
- The piloreceptor is the arrector pili, a small muscle attached to hair follicles in mammals.
- Hair functions as a warning system, for heat retention, identification, and vestigially.
Nail
- The nail is an extension of the stratum corneum, consisting of dead keratinocytes densely packed with parallel hard keratin fibers.
- It is a distinguishing characteristic of primates.
- It allows for more sensitive and tactile finger tips.
- It functions as a tool for picking and manipulating objects.
Glands
- There are two types of glands: endocrine and exocrine.
- Exocrine glands use ducts to transport their products.
- Examples of exocrine glands include:
- Merocrine glands: produce water perspiration for temperature regulation and waste removal.
- Apocrine sweat glands: produce pheromones and are stimulated in response to stress and sexual stimulation.
- Sebaceous glands: produce sebum, which keeps the skin from becoming dry and brittle and makes hair shiny.
- Ceruminous glands: produce secretions that combine with sebum to form ear wax.
- Mammary glands: produce milk.
Tissues
- Tissues are a collection of specialized cells that function together.
- Matrix is non-living, extracellular material that surrounds the cells.
- There are four categories of tissues: epithelial, nervous, connective, and muscle.
Epithelial Tissues
- General characteristics:
- Line surfaces and cover surfaces.
- Avascular: no blood supply.
- Tightly packed cells with little to no space between cells.
- Highly mitotic: reproduce rapidly.
- Have a basement membrane at their deepest point.
- Functions:
- Protection.
- Secretion.
- Excretion.
- Absorption.
- Filtration.
- Sensation.
Connective Tissue
- Consists of mostly non-living matrix with widely spaced cells.
- It is vascular: has a blood supply.
- Functions:
- Binding of organs or enclosing of organs.
- Support of the body.
- Physical protection of vital organs.
- Immune protection.
- Movement.
- Energy storage.
- Heat production and temperature regulation.
- Transportation of nutrients and gases via blood.
Fibrous Connective Tissue
-
Matrix contains significant amounts of protein fibers.
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Cell types:
- Fibroblast: produce the fibers and ground substance.
- Mast cells: secrete hormones that regulate blood flow and clotting.
- Macrophages: ingest and help get rid of particles and infections microorganisms.
- Leukocytes: WBC that play various protective roles.
- Plasma cells: specialized WBC that help with immunity.
- Adipocytes: fat-storing cells.
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Matrix: non-living material around the cells (has fibers and ground substance).
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Fibers are found in three forms:
- Collagenous: made out of protein collagen.
- Reticular: have thin collagen fibers.
- Elastic: made out of protein elastin.
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Description
This quiz covers the characteristics of ground substance and areolar connective tissue, including their structures and functions in the body.