Chapter 5 Flashcards
What are the three primary germ layers? Name one example of each.
- Ectoderm: epidermis
- Mesoderm: Cardiac Muscle
- Endoderm: Respiratory Tract lining
Describe three functions of epithelial tissues.
- Protects deeper tissue from injury
- Produce chemical secretions
- Excrete Waste
- Absorb nutrients
Identify the three types of cell junctions
Tight
Desmosomes
Gap Junctions
What is a key characteristic of Tight junctions?
linkage between two adjacent cells by transmembrane cell-adhesion proteins
- Located near apical pole
- Seals off intracellular surface making it difficult for a substance to pass between cells
What is a key characteristic of Desmosomes?
patches that hold cells together like a clothing snap
- Keeps cells from pulling apart,
- Resists mechanical stress
- Hemi-desmosomes are half, that anchor basal cells of an epithelium underlying basement membrane
What is a key characteristic of Gap Junctions?
formed by ring-like connexons
- Ions, nutrients and small solutes pass between cells
- Located in cardiac and smooth muscle and embryotic tissues
Identify the four main classes of connective tissues.
- Connective Tissue Proper
- Cartilage
- Bone
- Blood
Two important functions of connective tissue
- Binding of organs
- Support for bones and cartilage
What are the three main fiber types that provide support in connective tissues?
Collagenous Fibers: most abundant, touch, flexible, ex: tendons, ligaments, deep skin
Reticular Fibers: thin, highly branched, coated with glycoprotein, ex: spleen/ lymph nodes
Elastic Fibers: thinnest, made from elastin, allows stretch and recoil
What are the three main types of membranes?
- Cutaneous
- Mucous
- Serous
What are characteristics of cutaneous membranes?
:skin, largest membrane in the body
- Stratified squamous epithelium
- Relatively dry layer
- Protection
What are characteristics of Mucous membranes?
: lines passages that open to the external environment
- Digestive tract
- Goblet cells
- Sublayers: epithelium, lamina propria, muscular mucosa
What are characteristics of serous membranes?
lines cavities that are closed to the exterior
- Simple squamous epithelium
- Produced serous fluid that arises from blood
- Covers organs and lines walls of body cavities
Endothelium lines blood vessels and hear
Mesothelium lines body cavities (pericardium, peritoneum, pleura)
Identify and contrast the two major ways to repair tissue. Identify one tissue that has a great repair capacity and one that has no repair capacity.
Regeneration: replacement of dead or damaged cells by a cell of the same type
- Restores normal function
- Ex: minor skin or liver injuries
Fibrosis: replacement of damaged cells with scar tissue
- Scars hold organs together, but doesn’t restore function
- Ex: severe cuts, burns, scarring of lungs in tuberculosis
Capillaries are vessels only a single cell layer thick. This allows for rapid exchange of oxygen, nutrients, carbon dioxide, and wastes. What specific epithelial tissue do you think makes up the capillaries?
Simple Epithelia
A woman in labor is often told to push. In doing so, is she consciously contracting her uterus to expel the baby? Justify your answer based on the muscular composition of the uterus.
- No. The uterus is a smooth (and thus, involuntary) muscle. What she is really contracting are her abdominal muscles, which in turn help the uterus to move the baby down.
When cartilage is compressed, water is squeezed out of it, and when pressure is taken off, water flows back into the matrix. This being the case, why do you think cartilage at weight-bearing joints such as the knees can degenerate from lack of exercise?
- Lack of exercise leads to poor oxygen and deficient nutrient delivery to the cartilage. This slowly and gradually leads to degeneration of cartilage particularly at weight bearing joints (as seen in knees) and cartilage undergoes necrosis.
The epithelium of the respiratory tract is mostly of the pseudostratified columnar ciliated type, but in the alveoli – the tiny air sacs where oxygen and carbon dioxide are exchanged between the blood and inhaled air – the epithelium is simple squamous. Explain the functional significance of this. That is, why don’t the alveoli have the same kind of epithelium as the rest of the respiratory tract?
The alveoli have to have an epithelium that allows for easy gas exchange. Columnar epithelium would not exchange it easy or fast at all.
