Download Membranes:

Membranes:
• Epithelial tissue + Connective tissue
• Mucus membranes
• Serous membranes
• Cutaneous membranes
• Synovial membranes
Mucous Membranes
Mucous membranes (mucosae)
• Line organs with connections to the outside environment
(mouth, intestines, nasal passages, etc.)
• Usually composed of either stratified squamous or simple
columnar epithelium covering a layer of loose connective
tissue
• Submucosa : connective tissue layer that connects the
mucosa to underlying structures
Mucous Membranes
Mucous membranes (mucosae)
• May contain goblet cells or multicellular glands
– Can produce large quantities of mucus
– Mucus consists primarily of water, electrolytes, and the
protein mucin
• Some mucosae also can absorb (e.g., the epithelial layer in
the intestine)
Serous Membranes
Serous membranes (serosae)
• Line walls and cover organs of body cavities (e.g., thorax and
abdominopelvic cavities)
• Consist of a continuous sheet doubled over on itself to form two
layers
• Pericardium
• Pleura
• Peritoneum
• The portion of the membrane that
covers the outer surface of organs
is called the visceral layer.
• The portion of the membrane that
lines the cavity wall is called the
parietal layer.
Serosal Fluid
• “Serous fluid” – watery, thin, composed of water and enzymes
• Creates moist, slippery surface, reduces friction between
organs and cavity surfaces
• Serous fluid is called transudate
– Location of transudate
• Thorax – pleural fluid
• Abdomen – peritoneal fluid
• Heart – pericardial fluid
Some medical terms
• Hemothorax
– Injury to thoracic cavity, such as broken rib, the blood
and other cells leak from ruptured capillaries into the
pleural space and create a hemothorax
• Effusion – excessive fluid
– Abdominal Cavity – called ascites
– Thoracic Cavity – called pleural effusion
– Heart – pericardial effusion
– Causes –congestive heart failure, peritonitis
• Transudate: A fluid that passes through a membrane, which
filters out all the cells and much of the protein, yielding a
watery solution.
• A transudate is a filtrate of blood. It is due to increased
pressure in the veins and capillaries that forces fluid
through the vessel walls or to a low level of protein in blood
serum.
• Transudate accumulates in tissues outside the blood vessels
and causes edema (swelling).
Cutaneous Membrane
• Also called integument (or, more simply, skin)
• Composed of an outer keratinized stratified
squamous epithelium, or epidermis
• Epidermis is attached to an underlying layer of
dense irregular connective tissue called the
dermis.
• Dermis contains collagenous, reticular, and
elastic fibers which enable skin to be both strong
and elastic
Diagnosing by mucous membrane clues:
• Are they Dry or Moist?
Dehydration = dry, “tacky”
• Capillary Refill Time- the time it takes for blood to return
to the capillaries
>2 sec – low blood pressure, compromised cardiac output
< 1 sec – high blood pressure, hypercompensated state
Synovial Membranes
• Line the cavities of joints
• Composed of loose connective tissue and adipose tissue
covered by a layer of collagen fibers and fibroblasts
• Manufacture the synovial fluid that fills the joint spaces
• No epithelial cells!
• What Color?
Yellow = elevated bilirubin
icterus (condition), juandice (appearance)
can be caused by liver failure, hemolytic anemia
Blue = lack of oxygen, tissues are not receiving adequate
oxygen (obstruction, pneumonia - airways)
called hypoxia
Bright Red = increased blood flow (allergic reaction,
fever), the term for this is hyperfused
hyperemia
White/ Pale = anemia, shock, hypothermia
Muscle Tissue
• Composed of specialized proteins actin and myosin fibers
• Three types of muscle tissue
– Skeletal
– Smooth
– Cardiac
Skeletal Muscle
• Large cells (foot long or more!)that contain hundreds
of nuclei and mitochondria
• Usually controlled through conscious efforts
(voluntary muscle)
• Skeletal muscle cells are striated.
• Skeletal muscle cells are bundles of fibers
held together by loose connective tissue.
• Voluntary Striated Muscle
Smooth Muscle
• Composed of small, spindle-shaped cells
that lack striations
• Smaller cells than skeletal muscle
• Muscle contractions cannot be consciously
controlled (nonstriated involuntary muscle)
• Found in the walls of hollow organs, in
exocrine glands, and along the
respiratory tract
– Responsible for peristalsis in
gastrointestinal tract, constriction
of blood vessels, and emptying of
urinary bladder
Cardiac Muscle
• Found only in the heart
• Also smaller cells
• Entirely involuntary and striated
• Cardiac muscle cells connected to
one another via intercalated disks
(intercellular junction)
Nervous Tissue
• Found in the brain, spinal cord, and peripheral nerves
• Composed of two general cell types:
– Neurons
– Supporting neuroglial cells
Nervous Tissue
Neurons
• Longest cells in the body;
three primary parts:
– Perikaryon – the cell body;
contains the nucleus
– Dendrites – short cytoplasmic
extensions; receives impulses
– Axons – long, single extension;
conducts impulses away from
the cell body
Neuroglial cells
– Support the neurons