BIOL126 Lecture Notes - Lecture 4: Simple Columnar Epithelium, Pericardium, Pleural Cavity
10 Jun 2018
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Tissues
2.7 What is a tissue?
-Groups of cells work co-operatively together to form tissues
-Tissues perform specific functions as a group
-Cell structure and function is related to tissue function
2.7.1 the four basic tissue types in the body
•Muscle
•Neural (Nervous)
•Epithelial
•Connective
2.7.2 their locations and functions
Muscle tissue:
•Primary function is to contract or shorten
•Controlled contraction allows movement in the body
•Three types of muscle tissue: cardiac, skeletal and smooth
Neural/ nervous tissue:
•Primary function: to conduct electrical impulses throughout the body
•Information contained in pattern and frequency of impulses
•Neurons transmit impulses; neuroglia support neurons
Epithelial tissue:
•Lines and covers internal and external body surfaces:
-cells tightly interconnected
-avascular (no blood vessels), so sits on basement membrane of connective tissue)
•Functions: physical protection from abrasion and chemicals; protection from dehydration; allows
sensation; forms glands which produce secretions
Connective tissue:
•All connective tissues (CT) apart from blood and lymph (no fibres) have the same basic
construction
•Background matrix; cells; protein fibres eg. Areolar (loose) CT has gel matrix, collagen and
elastin fibres, fibroblasts and macrophages. Note: A “blast” is a “building” cell
•Functions: connects epithelium to rest of body; provide structure; store energy reserves;
transport materials throughout the body
2.8 The different types of epithelial tissue
•Specialisations:
1. Cilia (beat in unison to sweep substances across cell surface)
2. Microvilli (increase surface area for absorption , secretion or diffusion)
3. Keratin (protein to waterproof inside of skin (epithelial) cells)
2.9 The types of membrane found in the body, where they are found and what they do
•Different types of anatomical membranes in the body
- cell/plasma membrane encloses cell contents
- tissue membranes also physical barriers
- line or cover other tissues
2.9.1 mucous
•Line passageways and chambers that communicate with the exterior of the body
•Includes digestive, respiratory, reproductive and urinary tracts
•Moisture is important in these passageways to reduce friction, and/or to assist in absorption or
secretion
•Lubrication/moisture provided by mucous cells, multicellular glands, or exposure to fluids eg.
semen or urine
•Connective tissue component is the Lamina propria
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•Mucous membranes may have simple epithelia with a secretory or absorptive function eg. simple
columnar epithelium in the digestive tract
•Other types of epithelia include stratified squamous epithelium in the mouth, and transitional
epithelium along most of the urinary tract and in the bladder
2.9.2 serous
•Line the sealed, internal subdivisions of the body cavities i.e. those that do not communicate with
the body’s exterior
•Mesothelium supported by areolar (loose connective) tissue
•Very thin, transparent, and firmly attached to the tissue surface
•Parietal (cavity surface) and Visceral (serosa on outside of organ) form two opposing layers
•Major function to reduce friction between opposing surfaces- produce a transudate/fluid
•Three types:
1. Pleura; lines pleural cavities and covers lungs
2. Peritoneum; lines peritoneal cavity and covers the organ surfaces
3. Pericardium; lines pericardial cavity and covers heart
Problems:
•Build up of serous fluid causes problems in the body
•Caused by inflammation of the membrane eg. due to friction,infection, injury
•Pleuritis/Pleurisy; Pericarditis; Peritonitis and Ascites
•Ascites = characteristic abdominal swelling
•Contained fluid puts pressure on, and distorts abdominal organs
•Causes lower back pain, heartburn and indigestion
2.9.3 cutaneous
•Skin: covers the external body surface
•Stratified, squamous epithelium (epidermis) with a layer of areolar tissue below, supported by
dense, irregular connective tissue (dermis)
•Unlike mucous and serous membranes, the cutaneous membrane is thick, fairly waterproof, and
usually dry.
2.9.4 synovial
•Lines the cavity of synovial joints
•Thick and moist
•Produces synovial fluid which lubricates the articulating surfaces, and moves into the cartilage
providing oxygen and nutrients
•Comprised of areolar tissue containing a matrix of interwoven fibres, proteoglycans and
glycoproteins
2.10 The difference in function and location of simple and stratified epithelial membranes
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