What are the levels of organization in the body (ascending order from smallest unit to largest unit).
Chemical - cellular - tissue - organ - system - organism
Which unit that composes the body is the smallest unit of life?
Cellular
True or False: Cells work independently
False. Cells do not operate independently, they work together.
Epithelial tissue
A tissue which covers the body, lines body cavities, and forms glands
Connective tissue
A tissue which binds and supports various organs
Muscle tissue
Contractile tissue
Nervous tissue
Initiates and conducts electrochemical impulses
What are the four basic tissue types?
Epithelial, connective, muscular, nervous
What is a microtome?
The instrument that sections slide tissues
True or False: Only one tissue type at a time will be shown on a microscope slide
False. Some slides may be used to examine more than a single tissue type
What is the thinnest epithelium found in the human body?
Simple squamous epithelium
Where is the simple squamous epithelium present?
Areas with diffusion (and gas exchange). Ex:
The heart
Blood vessels
Lymphatic vessels
Forming capillary walls
Which type of cell resembles “fried eggs”?
Simple squamous
What is the function of simple cuboidal epithelium?
Secretion and absorption. Ex:
Thyroid gland
Kidney tubules
Ducts of many glands
Function of simple columnar epithelia
Absorption and secretion. Ex:
Stomach
Small and large intestines
Ducts if various glands (line)
Which cells have goblet cells?
Simple columnar epithelia
What is the role of goblet cells?
They produce mucus which acts as a lubricant and protective barrier. Very abundant in some parts of the digestive tract.
Characteristics of individual cells in stratified squamous epithelium
Bottom cells (closer to basement membrane) are often cuboidal, but top cells (closer to apical surface) are often squamous
Where are stratified squamous epithelia often found?
In areas of the body that are subject to “wear and tear”
Nonkeratinized vs. keratinized. What cell type could this be applied to?
Nonkeratinized: Absence of keratin Keratinozed: Presence of keratin This can be applied to stratified squamous epithelium
Keratinized cells at the surface of stratified squamous epithelial are (alive/dead)
Dead
In simple terms, what is a keratinized tissue?
Skin
What does transitional epithelium line? What makes this epithelium unique?
The urinary bladder, the urethra, the upper portion of the urethra. The thickness of this epithelium changes as it is subject to pressure.
Function of glandular epithelia. Where are they found?
Secretion. Found beneath the covering epithelia as single cells/cluster cells
What are glands specialized for?
To produce and secrete substances into ducts that open onto surfaces (exocrine glands) or secrete substances into body fluids (endocrine glands)
Exocrine vs. endocrine glands
Exocrine: release onto surfaces Endocrine: secrete into body fluids
Name for glands that release their fluids by exocytosis. Examples?
Merocrine (eccrine).
Salivary glands
Sweat glands of the skin
Pancreatic glands
Glands that pinch off portions of the cell as part of the secretion. Example?
Apocrine glands.
Mammary glands
Whole cells filled with secretion are released. Example?
Holocrine glands
Sebaceous glands of the skin
What is the most wide-ranging and abundant type of tissue in the body?
Connective tissue
Functions of connective tissue
Mechanical binding and support, circulation of body fluids, insulation, storage of food reserves, inflammation
What are the 3 structural features that all connective tissues have in common?
Cells
Protein fibres
Ground substance
Fibres and ground substance together form the:
Extracellular matrix of connective tissues
Is cartilage vascular or avascular?
Avascular
Types of connective tissue proper
Areolar (loose) connective tissue
Adipose connective tissue
Reticular connective tissue
Dense regular connective tissue
What are the 2 supporting connective tissues?
Cartilage
Bone
True or False: The consistency of the ground substance does not vary
False. It varies from fluid, to gel, to solid.
What are components of the ground substance?
Glycosaminoglycans (GAG) such as sulphate and hyaluronic acid.
Proteoglycan
Adhesive glycoproteins
Cell names ending in “-blast” are (mature/immature)
Immature
Cell names ending in “cyte” are (mature/immature)
Mature
Roles of immature cells (blasts)
Secrete matrix and are actively mitotic
Roles of mature cells (cytes)
Maintaining the matrix. Are less active
What are the 3 types of fibres of connective tissue?
Collagen
Elastic
Reticular fibres
Fibroblast
Actively mitosis cell that secreted ground substance and fibers
Mast cell
Has coarse, dark-staining granules (in the cytoplasm). Secrete heparin and histamine
Macrophages
Large and irregularly shaped phagocytize cells. Arise from monocytes (type of white blood cell). Wander through connective tissue where they engulf and destroy bacteria, foreign particles, and dead/dying body cells.
Heparin
A chemical that inhibits blood clotting
Histamine
A chemical that increases blood flow by dilating blood vessels
What does reticular connective tissue form?
Internal framework of the spleen, liver, bone marrow, and lymph nodes. Also closely associated with blood vessels and nerves
What do cells in reticular connective tissue contain?
Fibroblasts (reticular cells)
White blood cells
Macrophages
Characteristics of reticular fibres
Short, thin branched network of collagen-like fibres
What characterizes an adipose cell/adipocyte?
A large internal lipid droplet which displaces the nucleus to the edge of the cell
What are dense connective tissues characterized by?
An abundance of fibers
2 types of dense connective tissue
Regular
Irregular
What sets apart dense irregular tissue from dense regular?
They have the same structural components, but dense irregular’s bundles of collagen fibers are much thicker and run in several directions
Where is dense regular connective tissue found?
In the skin dermis. Forms fibrous coverings around organs such as kidney, muscles, bones, and nerves.
3 types of cartilage found on the human body
Hyaline cartilage
Elastic cartilage
Fibrocartilage
Most types of cartilage are surrounded by a layer of:
Perichondrium
What is perichondrium?
Dense connective tissue.
What is the most common type of cartilage?
Hyaline cartilage
Most of the embryonic skeleton is formed of:
Hyaline cartilage
Where are collagen fibers in the cartilage embedded?
In the gel-like matrix
Where is hyaline cartilage found in an adult human?
Articular surfaces of bones
Ends of the ribs
Part of the nasal septum
Larynx
Trachea
Bronchi
Compare fibrocartilage to other cartilage types
Fibrocartilage is less organized than other cartilage types, and it lacks a perichondrium
Characteristics of fibrocartilage
It provides strong support and can withstand heavy pressure. It forms pads, the vertebral discs between the individual vertebrae and the knee menisci between the tibia and femur. Also forms pubic symphysis (the joint between the pubic bones of the pelvis)
Function of bones
Support and protection. Provide cavities for fat storage and synthesis of blood cells. Storehouse for the minerals, calcium, and phosphorus required for various functions.
What are the two basic types of bone?
Spongy (cancellous)
Compact
Cancellous vs. compact bone
Cancellous: Found internally (generally at expanded ends of bone known as trabeculae). Compact: External layer of the bone. Is thickest along the length of the bone.
The spaces between the spongy bone trabeculae are filled with:
Bone marrow
What does an osteon consist of?
Concentric rings of bone called lamellae around a central (Haversian) canal containing blood vessels and nerves
What is the name for mature bone cells?
Osteocytes
Where are osteocytes found?
In lacunae between lamellae
Is bone vascular or avascular?
Vascular (highly)
Periosteum
A connective tissue layer surrounding the bone
How do blood vessels located in the periosteum work?
They penetrate compact bone through transverse perforating (Volkmann) canals which connect to the central canals that run longitudinally through the bone.
What are canaliculi?
Networks of small canals that radiate from each lacunae
How do individual osteocytes obtain nutrients and remove wastes?
Via their cytoplasmic extensions that occupy canaliculi.
Acid removes inorganic salts from bone, which causes the bone to become soft (the bone is decalcified). What characteristics of bone are provided by inorganic salts?
Inorganic materials/salts determine the bone's density
Baking bones removes the organic constitutes from the bone, which causes the bone to become brittle. What characteristics of bone are provided by the organic materials?
Organic materials determine the bone's flexibility
What type of epithelium is found lining the urinary bladder?
Transitional epithelium
What type of epithelium is found lining the small intestine?
Simple columnar
What type of epithelium is found lining the trachea?
Pseudostratified
What type of epithelium is found forming the epidermis of the skin?
Keratinized stratified squamous epithelium
What type of epithelium is found forming the blood capillaries?
Simple squamous
What kind of epithelium is best designed for: Absorption
Cuboidal and columnar
What kind of epithelium is best designed for: Rapid diffusion
Simple squamous
What kind of epithelium is best designed for: Protection
Stratified squamous
What type of connective tissue forms the framework of the liver, spleen, and lymph nodes?
Reticular connective tissue
What type of connective tissue fills in the spaces between organs and holds them in place?
Areolar (loose) connective tissue
What type of connective tissue composes tendons and ligaments?
Dense regular connective tissue
What connects muscle to bone?
Tendons
What connects bone to bone?
Ligaments
Why is bone a much thicker tissue than cartilage?
Bone is vascular and can continue to grow larger and larger. Cartilage is avascular and only has a "set" size to grow until. It receives its nutrients from diffusion which is not enough to grow extremely large.