Section 3 Flashcards
Section 3, Module 1
What are the 4 basic types of tissue in the human body that are the building blocks for every organ?
Epithelial tissue, connective tissue, nervous tissue and muscular tissue
What are the two types of epithelium, and describe them briefly?
- Covering epithelium: Cells that cover the external and internal surfaces
- Glandular epithelium: cells that produce and secrete product, such as hormones
True or false:
Epithelium is composed of closely apposed cells.
True:
Epithelium is composed of closely apposed (side by side) cells with very little or no intervening cellular substance.
Explain how epithelial cells are joined together.
Adjacent epithelial cells are joined by specialized junctions. (tight junctions, adhering junctions, desmosomes, and gap junctions)
What are the four different types of junctions that adjacent epithelial cells are joined by?
Tight junctions, adhering junctions, desmosomes, and gap junctions
(just know the names, they’re discussed more in PHGY 170)
Describe the polarity of an epithelial cell.
An epithelial cell has an exposed (apical) surface that faces the exterior of the boy or internal space, and a basal surface where it is attached to the underlying tissue.
How are epithelial cells separated from the underlying tissue?
Epithelial cells rest on and are attached to the basal lamina (basement membrane) which separates it from the underlying tissue.
How do epithelial tissues receive nutrients?
Epithelial cells have no direct blood supply. The epithelial cells receive nutrients from the blood vessels in the underlying tissue.
Are epithelial cells renewed?
Yes, epithelial cells are renewed continuously.
List and describe the functions of epithelium.
- Support and protect (it covers and lines external and internal surfaces of the body protecting the underlying tissue from injury, pathogens, and dehydration. E.g, skin)
- Permeability (it allows substances to be absorbed into the body. E.g, epithelium lining the digestive system absorbs nutrients from the food)
- Sensation (some contain specialized cells that are able to detect sensory stimuli. E.g skin senses touch, tongue senses taste)
- Secretion (some are specialized to secrete specific substances. E.g, skin secretes lubricating oil, enzymes and hormones are secreted by digestive system)
Name some of the functions of epithelial tissue.
- cover and line surfaces
- protection (skin)
- permeability (absorption in the digestive system)
- sensation (skin)
- contractility/secretion (of glandular cells)
Identify the difference between simple and stratified epithelia.
Simple is only one cell layer thick, whereas stratified is two or more.
What is squamous epithelia shape?
Flat (thin), wide, and somewhat irregular in shape
What is cuboidal epithelia shape?
About the same size on all sides; the nucleus is usually centrally located
What is columnar epithelia shape?
Taller than they are wide; nucleus is oval and located in the basal region of the cell
How are epithelial tissues named? (First name + last name)
a) cell organization + cell shape
b) cell shape + cell organization
a) cell organization + cell shape
E.g, simple squamous
E.g, stratified columnar
What is simple squamous epithelium and what are some examples of where it is found?
It is a simple squamous epithelium that consists of a single layer of flattened cells.
It can be found lining blood vessels.
Why is it useful that blood vessels are lined with simple squamous epithelium?
Blood vessels transport materials to and from cells, and for energy efficiency it should have a thin barrier allowing for rapid exchange
The single layer of flattened cells provides a thin barrier between vessels and tissues, allowing material to travel a short distance between the two.
What is simple cuboidal epithelium and what are some examples of where it is found?
Consists of a single layer of cube cells.
For example, can be found lining some glands.
What is simple columnar epithelium and what are some examples of where it is found?
Consists of a single layer of column shaped cells.
It can be found lining the gastrointestinal tract.
Why is it useful that the gastrointestinal tract is lined with simple columnar epithelium?
The single layer cells allows for rapid secretion or absorption of material.
What is stratified squamous epithelium and what are some examples of where it is found?
It has multiple layers of flat shaped cells.
The basal cells may be more cuboidal in shape, but the apical (superficial) cells display a squamous flattened shape.
For example, it makes up the most superficial layer of skin as multiple thin layers of small cells. This allows the skin to protect deeper structures from abrasion and damage.
What is stratified cuboidal epithelium and what are some examples of where it is found?
Contains multiple layers of cube shaped cells.
Can be located in ducts of some glands. Functions of these cells include secretion, protection, and strengthening the walls of ducts of glands.
What is stratified columnar epithelium and what are some examples of where it is found?
Contains multiple layers of column shaped cells.
It is relatively rare in the human body, but they can be found in the male urethra. The function of these cells include protection and secretion.
Describe transitional epithelium and some of its characteristic features. Also provide an example.
It consists of multiple layers of epithelial cells that allows for stretching.
Varies in shape depending if its relaxed (dome shaped surface cells) or stretched (flattened out surface cells).
In the urinary bladder, epithelial cells are able to change shape as urine accumulates in the bladder.
Describe pseudostratified (ciliated columnar) epithelium and some of its characteristic features. Also provide an example.
A single layer of cells and has its cell nucleus positioned in a manner suggestive of stratified epithelium.
The short cilia (hair like projections) on the surface of these cells help in moving mucous.
Found mostly throughout the respiratory tract, where mucous must be transported. (e.g lining the nasal cavity)
What are the functions of connective tissue?
- Support and protection: The bones of the skull protect the brain. The kidneys are surrounded by a fat padding that protects it.
- Structural framework for the body: Cartilage supports body structures such as the windpipe (trachea) ears, and nose. Bones provide framework for skeletal muscles.
- Medium for exchange of nutrients and metabolic waste: blood serves as a medium that carries gases, nutrients, wastes, and blood cells to different parts of the body.
- Storage and repair: bone stores minerals such as calcium; fat serves as a major energy reservoir for the body.
- Defense: acts as a physical barrier, through white blood cells (macrophages, neutrophils), and antibody production (plasma cells).
What is the difference between fixed and wandering connective tissue cells?
Fixed means that they are permanent residents in the connective tissue (e.g, fibroblasts)
Wandering means that they are transient migrants who have entered the connective tissue from the blood in response to specific stimuli (e.g, macrophages which are white blood cells)
What are the three different types of fibres secreted by fibroblasts?
Collagen, reticular and elastic fibres.
How do different types of fibers contribute to connective tissues functions?
Different components and proportions of fibre types lead to diverse functions of various connective tissue.
What is the ground substance of connective tissue?
The ground substance occupies the space between the cells and fibres of connective tissues. It has high water content, is transparent, colorless, and viscous.
What are the three types of connective tissue, and their features?
- Connective tissue proper
- loose: has more ground substance with few CT fibres (example adipose tissue)
- dense: has less ground substance with more CT fibres (example elastic tissue) - Supporting connective tissue
- bone: framework of the body
- cartilage: structural component - Specialized (fluid) connective tissue
- blood: fluid within blood vessels and the heart. contains various cells and proteins and performs a number of essential functions within the body.
- lymph: interstitial fluid (fluid that bathes cells) that is collected into thin-walled lymphatic vessels and transported to the cardiovascular system.
What type of connective tissue is adipose tissue? Also explain how the advantages of it.
Connective tissue proper (loose connective tissue)
Adipose tissue is a specialized type of loose connective tissue where fat cells (adipocytes) account for most of the volume of this tissue. This tissue acts as a padding, insulates against heat loss through the skin, and serves as a packing or filler around and between structures.
What type of connective tissue is elastic tissue? How does this contribute to its function?
Elastic tissue is a specialized type of dense regular connective tissue composed of bundles of thick parallel elastic fibres between which we find some collagen and fibroblasts. Due to its fibrous nature, this tissue has the ability to stretch and recoil.
What is Ehlers-Danlos syndrome and its symptoms?
EDS is a genetic disorder that can cause defects in collagen. Without the proper form of collagen, people with EDS have symptoms that affect functions of the muscular and skeletal systems.
This can cause laxity or “looseness” in tissue. Lax tissue can present in the following symptoms:
- loose skin with high elasticity or stretch
- fragile skin that cannot resist large forces
- flexible joints leading to joint pain, and eventually arthiritis
- other symptoms
What is supporting connective tissue, and two types of it?
It provides a strong, durable framework to protect and support soft body tissues.
Cartilage and bone are two types of supporting connective tissue.
What is cartilage and where is it found?
- A supporting connective tissue (structural component of the body)
- a firm tissue, but softer and more flexible than bone
Found in many areas including:
- the joints between moveable bones
- between vertebrae in the spine
- ears and nose
- bronchial tubes or airways
What types of cells, fibres and ground substance are found in cartilage?
Cells: primarily chondrocytes, which are located throughout the ground substance in small spaces called lacunae that contain one or more cells
Fibres: can include various collagen or elastic fibres scattered throughout the cartilage.
Ground substance: a firm gel that makes cartilage solid. However, cells called chondrocytes are located throughout the intercellular substance.
What is perichondrium in cartilage?
Dense, irregular connective tissue that envelops cartilage to provide nutrients to the cartilage. Not all types of cartilage have a perichondrium.
What is lacunae in cartilage?
Small spaces in cartilage that house one or more chondrocytes (the major cells of cartilage)
Why do some types of cartilage have a perichondrium?
Cartilage is avascular, therefore unable to get nutrients from a direct blood supply. The perichondrium is present to help provide nutrients to the cartilage and remove waste products.
What are the three major types of cartilage?
Hyaline, fibrocartilage, and elastic
What is the location of the different types of cartilage?
Hyaline: joint surface of moveable joints, walls of the nose, trachea, bronchi (upper respiratory tract), and ribs.
Fibrocartilage: intervertebral discs, and symphysis pubis.
Elastic: External ear, Eustachian tube (connects ear to nose), and epiglottis (barrier to trachea during swallowing food or drink)
What are the anatomical characteristics of each type of cartilage? (Basically describe all three of the tissues)
Hyaline: wear-resistant tissue that is designed to bear and distribute weight. Strong, rubbery, flexible tissue. Most common type of cartilage.
Fibrocartilage: tough and inflexible. Durable and resistant to compression.
Elastic: more flexible than hyaline cartilage.
What are some functions of bone?
- support
- locomotion
- protection
- blood cell production
- mineral metabolism
Distinguish between inorganic and organic bone.
Organic: cells, fibres, and ground substance
Inorganic: minerals and salts
Which component of bone provides for rigidity of bone?
a) organic
b) inorganic
b) inorganic (minerals and salts) mainly calcium phosphate
Describe the structure of bones.
The bone has a structured pattern of repeating cylindrical structures, known as osteons. Each osteon is made of concentric rings with a hollow central canal, AKA the Haversian canal. The cellular components of bone are located between concentric rings.
Provide some example of functions of connective tissue include:
- Support and protection
- Provides a structural framework for the body
- Medium for exchange of nutrients and metabolic waste
- Storage
- Repair
- Defense from invasion of antigens
