Tissues Flashcards
What is a tissue?
A group of one of more cell types which carry out specialized functions
What are the 4 main tissue types?
- Epithelial Tissue
- Connective Tissue
- Muscle Tissue
- Nervous Tissue
What are the characteristics of epithelial tissue?
- It covers internal and external free surfaces and organs
- The cells of tissues are closely packed
- Cells of epithelial tissue have both apical and basal surfaces where apical surface remains free and the basal surface is attached to the basement membrane
- No blood vessels are present in the tissue
- Tissue gets nutrients and oxygen from the underneath connective tissues
where do epithelial tissues get nutrients and oxygen?
from underneath connective tissues
Describe the 2 surfaces of an epithelial tissue
Cells of epithelial tissue have both apical and basal surfaces where apical surface remains free and the basal surface is attached to the basement membrane
Write the functions of epithelial tissue
- Protection
ex: barrier against mechanical injury, pathogens and fluid loss) - Absorption
ex: nutrients - Secretion
ex: enzymes
hormones
mucus
sweat
What do epithelial tissues secrete?
enzymes
hormones
mucus
sweat
How do epithelial tissues function in protection?
it acts as a barrier against mechanical injury, pathogens and fluid loss
What are the 2 types of epithelia?
Simple epithelia
Compound epithelia
Describe simple epithelia
It’s a single cell layer
ex:
- simple squamous
- simple cuboidal
- simple columnar
-pseudostratified columnar
Describe compound epithelia
Several cell layers
ex:
stratified squamous
transitional
Describe simple squamous epithelium
- It’s a single cell layer with plate-like cells
- This epithelium type is thin and leaky
- They’re found in places where materials exchange by diffusion
Ex: Alveoli, Blood capillaries
Describe the physical appearance of simple squamous epithelium
- It’s a single cell layer with plate-like cells
- This epithelium type is thin and leaky
Where is simple squamous epithelium found?
in places where materials exchange by diffusion
Give examples for simple squamous epithelium
Blood Capillaries
Alveoli
Describe simple cuboidal epithelium
- It’s a single cell layer with dice-shaped cells specialized for secretion
- It’s found in
kidney tubules
many glands
thyroid glands
salivary glands
Describe simple columnar epithelium
- It’s a single layer with large, brick-shaped cells
- It’s often found in places where secretion and active absorption is important
ex: intestinal lining
Describe simple columnar epithelium physically
It’s a single layer with large, brick-shaped cells
Where’s simple columnar epithelium found?
in places where secretion and active absorption is important
examples for simple columnar epithelium
ex: intestinal lining
describe simple cuboidal epithelium physically
It’s a single cell layer with dice-shaped cells specialized for secretion
Where is simple cuboidal epithelium found?
It’s found in:
kidney tubules
many glands
thyroid glands
salivary glands
Describe pseudostratified columnar epithelium
- this tissue consists of a single cell layer
- cells are not of equal height
- nuclei of cells are located at different levels. so, cells appear as several layers
- In many vertebrates, this epithelium has ciliated cells that form a mucous membrane and the cilia help sweep mucous along the surface
ex: nasal passage, trachea
Describe pseudostratified columnar epithelium physically
- this tissue consists of a single cell layer
- cells are not of equal height
- nuclei of cells are located at different levels. so, cells appear as several layers
What’s the purpose of a mucous membrane in pseudostratified columnar epithelium?
In many vertebrates, this epithelium has ciliated cells that form a mucous membrane and the cilia help sweep mucous along the surface
Where is pseudostratified columnar epithelium found?
nasal passage
trachea
Describe stratified squamous epithelium
- this tissue is composed of a number of cell layers
- this epithelium regenerates rapidly
- cell division produces new cells near the basement membrane
- the old cells are sloughed off and replaced by new cells
- this epithelium is found on surfaces where they are subjected to abrasion such as outer skin and lining of mouth, anus and vagina
where’s stratified squamous epithelium found?
on surfaces where they are subjected to abrasion such as outer skin and lining of mouth, anus and vagina
describe stratified squamous epithelium’s regeneration
- this epithelium regenerates rapidly
- cell division produces new cells near the basement membrane
- the old cells are sloughed off and replaced by new cells
What are the characteristics of connective tissue?
- Connective tissues are the most abundant tissues in the body that help connect organs and other tissues together structurally and functionally
- These tissues consist of different cell types scattered in a large amount of extracellular matrix containing different fiber types
- Matrix may be solid, semi solid (jelly like) or liquid
- Different cell types can be found in the matrix such as
- Fibroblasts - secrete fiber proteins
- Macrophages - engulf foreign particles/ any cell debris by phagocytosis
- Mast cells - secrete heparin and histamine
- Fat cells - storage and insulation
- leukocytes - protection
- There are 3 different fiber types
- collagen fibers: provide strength and flexibility
- reticular fibers - join connective tissues to adjacent tissues
- elastic fibers - make tissues elastic
3 different fiber types
- collagen fibers: provide strength and flexibility
- reticular fibers - join connective tissues to adjacent tissues
- elastic fibers - make tissues elastic
function of collagen fibers
provide strength and flexibility
function of reticular fibers
join connective tissues to adjacent tissues
function of elastic fibers
make tissues elastic
different cell types found in the matrix
- Fibroblasts - secrete fiber proteins
- Macrophages - engulf foreign particles/ any cell debris by phagocytosis
- Mast cells - secrete heparin and histamine
- Fat cells - storage and insulation
- leukocytes - protection
function of fibroblasts
secrete fiber proteins
function of macrophages
engulf foreign particles/ any cell debris by phagocytosis
function of mast cells
secrete heparin and histamine
fat cells function
storage and insulation
leukocytes function
protection
Describe the matrix
tissues consist of different cell types scattered in a large amount of extracellular matrix containing different fiber types
Matrix may be solid, semi solid (jelly like) or liquid
Different cell types can be found in the matrix such as
- Fibroblasts - secrete fiber proteins
- Macrophages - engulf foreign particles/ any cell debris by phagocytosis
- Mast cells - secrete heparin and histamine
- Fat cells - storage and insulation
- leukocytes - protection
There are 3 different fiber types
- collagen fibers: provide strength and flexibility
- reticular fibers - join connective tissues to adjacent tissues
- elastic fibers - make tissues elastic
What’s the most abundant tissue in the body?
connective tissue
functions of connective tissue
- Binding and structural support
- Protection
- Material Transport
- Insulation
What are the different types of connective tissue?
Areolar/Loose connective tissue
Fibrous/dense connective tissue
Adipose tissue
Blood
Cartilage
Bone
Describe loose CT / areolar tissue
- Most widely distributed CT in the vertebrate body.
- It is the generalized type of CT
- Cell types in this tissue are fibroblasts, macrophages, mast cells, fat cells and leukocytes
- Cell types in this tissue are fibroblasts, macrophages, mast cells, fat cells and leukocytes
- All 3 fiber types are found in this tissue
- Fibers are loosely arranged and wavy in nature
- This tissue binds epithelia and underlying tissue. So, it holds organs in place
- This tissue is found under the skin and throughout the body
Describe the cells in areolar tissue
- Cell types in this tissue are fibroblasts, macrophages, mast cells, fat cells and leukocytes
Describe the fiber types in areolar tissue
- All 3 fiber types are found in this tissue
- Fibers are loosely arranged and wavy in nature
Function of areolar tissue
- This tissue binds epithelia and underlying tissue. So, it holds organs in place
Location of areolar tissue
- This tissue is found under the skin and throughout the body
What’s the most widely distributed type of connective tissue in the vertebrate body?
Areolar tissue
What’s the generalized type of CT
Areolar tissue
Describe dense CT/ fibrous tissue
- This tissue is densely packed with collagen fibers
- So matrix is relatively reduced and contains fewer cells (fibrocytes)
- This tissue is found in tendons (attach muscle to bone) and ligaments (connect bones at joints) where tensile strength is required
location of fibrous tissue
- This tissue is found in tendons (attach muscle to bone) and ligaments (connect bones at joints) where tensile strength is required
describe matrix of dense CT
- This tissue is densely packed with collagen fibers
- So matrix is relatively reduced and contains fewer cells (fibrocytes)
Which tissue is densely packed with collagen fibers?
Dense CT
Describe adipose tissue
- This tissue is packed with adipose cells
- Each adipose cell contains a large, fat droplet
- This is a specialized type of CT which pads and insulates the body and stores fuel in fat molecules
- It’s found under the skin where it acts as a thermal insulator and energy store
Adipose tissue location
It’s found under the skin where it acts as a thermal insulator and energy store
Functions of adipose tissue
This is a specialized type of CT which pads and insulates the body and stores fuel in fat molecules
What does each adipose cell contain?
A large, fat droplet
Describe blood tissue
- It’s a specialized CT where the matrix isn’t secreted by blood cells and fibers are only formed during clotting
- The extracellular matrix is a liquid called plasma
- Blood plasma contains salts, water and dissolved proteins
- Cells such as RBC (transport respiratory gases), WBC (involved in defense) and platelets (involved in blood clotting) are suspended in the plasma
- Main functions of blood are transport of materials, defense and osmoregulation
When are fibers formed in blood tissue?
clotting
Components of blood plasma
salts, water and dissolved proteins
Cells in plasma
RBC (transport respiratory gases), WBC (involved in defense) and platelets (involved in blood clotting) are suspended in the plasma
Main functions of blood
transport of materials, defense and osmoregulation
Describe cartilage
- This tissue consists of a matrix composed of chondroitin sulphate which is a rubbery protein-carbohydrate complex
- Collagen fibers and chondrocytes are embedded in the matrix
- Chondrocytes secrete chondroitin sulphate and fibers
- This tissue provides support and flexibility at trachea and intervertebral discs
Composition of cartilage matrix
chondroitin sulphate which is a rubbery protein-carbohydrate complex
What components are embedded in cartilage matrix?
Collagen fibers and chondrocytes
Function of chondrocytes
secrete chondroitin sulphate and fibers
Function of cartilage
This tissue provides support and flexibility at trachea and intervertebral discs
Location of cartilage
Trachea, intervertebral discs
Describe bone
- It’s a mineralized CT
- Matrix consists of collagen fibers and inorganics salts
- The inorganic components are calcium, phosphate ions and magnesium
- The cells are osteoblasts (bone forming cells) and osteocytes (mature bone cells that maintain bone tissue)
- Osteocytes are enclosed within lacunae
- The mammalian bone has repeating units called osteons
- Each osteon has a concentric layer of mineralized materials
- AT the center of osteon is a central canal containing blood vessels and nerves
- This tissue forms endoskeleton in most vertebrates and provides strength and support to body
Composition of bone matrix
collagen fibers and inorganic salts
Inorganic components in matrix
phosphate ions, calcium, magnesium
cells in bone tissue
osteoblasts (bone forming tissue)
osteocytes (mature bone cells which maintain bone tissue)
How are osteocytes enclosed?
within lacunae
Describe osteons
- The mammalian bone has repeating units called osteons
- Each osteon has a concentric layer of mineralized materials
- AT the center of osteon is a central canal containing blood vessels and nerves
Define osteon
The mammalian bone has repeating units called osteons
What’s in the center of an osteon?
a central canal containing blood vessels and nerves
functions of bone
forms endoskeleton in most vertebrates and provides strength and support to body
Describe muscle tissue
- muscle tissue is responsible for movement
- cells in muscle tissue are composed of actin and myosin proteins
- this tissue is able to contract and relax
- 3 types of basic muscle tissue are found in human body: smooth muscle tissue, skeletal muscle tissue and cardiac muscle tissue
Describe smooth muscle
- Cells are spindle-shaped
- Uninucleated
- Intercalated discs absent
- Cells lack striations. No sarcomeres
- Sarcolemma present
- Sarcoplasm present
- Nervous supply by autonomic nervous system
- Neurogenic
- Involuntary
- Responsible for involuntary body functions such as churning of stomach and constriction of arteries
- Found in digestive tract, urinary bladder, arteries and internal organs
What components are cells in muscle tissue composed of?
actin & myosin proteins
shape of smooth muscle tissue
cells are spindle-shaped
functions of smooth muscle tissue
responsible for involuntary body functions such as churning stomach and constricting arteries
smooth muscle tissue location
internal organs
digestive tract
arteries
urinary bladder
shape of skeletal muscle tissue
composed of bundles of long cells
striations of skeletal muscle tissue
cells are striated
contractile units of muscle cells are sarcomeres
arrangement of sarcomeres along muscle cell gives a striated appearance
function of skeletal muscle
muscles are generally attached to skeletal system and helps mainly in voluntary body movements
shape of cardiac muscle tissue
composed of short cells interconnected via intercalated discs
functions of cardiac muscle tissue
cardiac muscle tissue is responsible for involuntary heart contractions
intercalated disks help relay signals from cell to cell and synchronize heart contractions
location of cardiac muscle tissue
wall of heart
describe the nucleated nature of muscle tissues
smooth and cardiac muscle tissues are uninucleated
skeletal muscle tissues are multinucleated
describe the striations of muscle tissues
in smooth muscle tissue, cells lack striations. no sarcomeres
in skeletal muscle tissue, cells are striated. contractile units of muscle cells are sarcomeres. arrangement of sarcomeres along muscle cell gives a striated appearance
cells are striated with sarcomeres
describe the intercalated discs of muscle tissues
no intercalated discs in smooth and skeletal muscle tissues
intercalated discs present in cardiac muscle tissue and help relay signals from cell to cell and synchronize heart contractions
describe nervous tissues
- nervous tissue contains neurons and glial cells
- neurons receive, process and transmit nerve impulses
- glial cells support neurons
describe neurons
- A neuron has an axon, dendrites and a cell body
- the basic structural unit of the nervous system is the neuron
- Dendrites and cell body receive nerve impulses from other neurons
- Axon transmits nerve impulses to other neurons, cells or muscles
- Axon is bundled together to form nerves
describe glial cells
- neuroglia cells are the supportive cells of neurons
- they
1. nourish nerve cells
2. insulate nerve cells
3. replenish neurons
4. sometimes moderate neuron functions
main parts of neuron
axon, dendrites and a cell body
the basic structural unit of the nervous system?
neuron
functions of cell body and dendrites
receive nerve impulses from other neurons
functions of axon
transmitting nerve impulses to other neurons, cells or muscles
what are supportive cells of neurons?
glial cells
functions of neuroglia
- nourish nerve cells
- insulate nerve cells
- replenish neurons
- sometimes moderate neuron functions
