Transcript Sexual Reproduction Development Tissues

TISSUES
Connective Tissue
the 3 primary germ layers
1. Ectoderm
2. Endoderm
3. Mesoderm

These give rise to all the basic tissues of the
body
The four types of tissues.
 Epithelial
 Connective
 Muscle
 Nerve
glandular epithelium & how is
it classified




A gland is one or more cells that makes and
secretes an aqueous fluid
Classified by:
Site of product release – endocrine or
exocrine
Relative number of cells forming the gland –
unicellular or multicellular
Glandular epithelium – made up of
cells that produce secretions
endocrine glands, what they secrete &
how do they do it



Ductless glands that produce hormones
Secretions include amino acids, proteins,
glycoproteins, and steroids
“Stuff” goes directly into blood
exocrine glands, what they secrete &
how do they do it






More numerous than endocrine glands
Secrete their products onto body surfaces (skin)
or into body cavities
Examples include mucous, sweat, oil, and
salivary glands
The only important unicellular gland is the
goblet cell
“stuff” goes through ducts
Sebum from sebaceous gland secretes acid
mantle on skin surface to kill bacteria
the major types of connective tissue &
some examples



Found throughout the body
Connective tissue proper, cartilage, bone, &
blood
All arise from the same stem cell



Endoderm becomes gastrointestinal tract,
respiratory tract, endocrine glands and
organs
Mesoderm becomes bones, cartilage,
blood, muscles
Ectoderm becomes the nervous system
and skin
the general functions of connective
tissue

Binding and support, protection, insulation,
and transportation
the common characteristics of
connective tissue




Mesenchyme as their common tissue of
origin
Varying degrees of vascularity
Nonliving extracellular matrix, consisting of
ground substance and fibers
Collagen is the main protein of ct
the major structural elements of
connective tissue


Ground substance – unstructured material
that fills the space between cells
Fibers – collagen (fibrous), elastic (elastin),
or reticular (fibrous)
types of cells you find in
connective tissue & where you find
them
 Fibroblasts
 Chondroblasts
 Osteoblasts
 Hematopoietic stem cells
 Found in mesenchyme, derived from
mesenchymal stem cells
Fibroblast
Chondroblast
Osteoblast
Hematopoietic stem cells
the two types of loose connective
tissue proper given & what
characterizes them
1. Areolar connective tissue
 Gel-like matrix with all three connective



tissue fibers
Fibroblasts, macrophages, mast cells, and
some white blood cells
Wraps and cushions organs
Widely distributed throughout the body
Areolar connective tissue
(loose)
Loose connective Tissue
Proper
2. Adipose connective tissue
 Matrix similar to areolar connective tissue



with closely packed adipocytes
Reserves food stores, insulates against heat
loss, and supports and protects
Found under skin, around kidneys, within
abdomen, and in breasts
Local fat deposits serve nutrient needs of
highly active organs
Adipose connective tissue
(loose)
the two types of dense connective
tissue proper & what characterizes
them
 Regular
 Parallel collagen fibers with a few elastic
fibers
 Major cell type is fibroblasts
 Attaches muscles to bone or to other
muscles, and bone to bone
 Found in tendons, ligaments, and
aponeuroses
Dense Regular (tendons)
Dense connective tissue
proper
 Irregular
 Irregularly arranged collagen fibers with
some elastic fibers
 Major cell type is fibroblasts
 Withstands tension in many directions
providing structural strength
 Found in the dermis, submucosa of the
digestive tract, and fibrous organ capsules
Dense irregular (fibrous
dermis)
the 3 different types of cartilage:
what they are made of, their
functions & where you would find
them
1. Hyaline cartilage
2. Elastic cartilage
3. Fibrocartilage cartilage
1. Hyaline Cartilage



Looks like jelly – does not heal and usually is
cut out when injured with hope of gaining
muscle to compensate for the loss
Chondrocytes lie in lacunae (a small space
containing an osteocyte in bone or
chondrocyte in cartilage)
Supports, reinforces, cushions, and resists
compression
Hyaline cartilage
 Forms the costal cartilage
 Found in embryonic skeleton, the end of long
bones, nose, trachea, and larynx
2. Elastic Cartilage



Similar to hyaline cartilage but with more
elastic fibers
Maintains shape and structure while
allowing flexibility
Supports external ear (pinna) and the
epiglottis
Elastic cartilage has
“little eyes”
3. Fibrocartilage cartilage



Matrix similar to hyaline cartilage but less
firm with thick collagen fibers
Provides tensile strength and absorbs
compression shock
Found in intervertebral discs, the pubic
symphysis, and in discs of the knee joint
Fibrocartilage
the characteristics & functions of
osseous tissue.


Hard, calcified matrix with collagen fibers
found in bone
Osteocytes are found in lacunae and are
well vascularized
Osseous Tissue
Osseous Tissue cont’d
 Supports, protects, and provides levers for
muscular action
 Stores calcium, minerals, and fat
 Marrow inside bones is the site of
hematopoiesis
 Bones will change shape with pressure:
braces/jawbone, tight shoes/bunions,
hammer toe
Bone marrow: 2 kinds
1. Red marrow – site of hematopoiesis
2. Yellow marrow – fat (this is why you make
soup from bones)
hematopoietic bone marrow of
flat bones  vertebrae,
sternum, ribs, iliac. It
represents 4-6% of body weight.
The fatty degeneration of red
bone marrow (RBM) (25%) into
yellow bone marrow (YBM) (75%)
is completed around age 21
years.
Red marrow
C  hematopoietic
tissue forming new
blood cells.
Yellow marrow
the characteristics & functions of
blood



Red (carry O2, CO2) and white cells (defense)
in a fluid matrix (plasma)
Contained within blood vessels
Functions in the transport of respiratory
gases, nutrients, and wastes
Blood