Histology Flashcards
(29 cards)
What are the four tissue types of the body?
epithelial, connective, muscular, and nervous tissue
What is an endothelium? Where are endothelia located?
Endothelium is a type of epithelium that lines the interior surface of blood vessels and lymphatic vessels, forming an interface between circulating blood or lymph in the lumen and the rest of the vessel wall. It is a thin layer of simple squamous cells called endothelial cells
. What is a basement membrane?
a thin, delicate membrane of protein fibres and mucopolysaccharides separating an epithelium from underlying tissue.
What are the different types of cell junctions?
Adherens junctions, desmosomes and hemidesmosomes (anchoring junctions)
Gap junctions (communicating junction)
Tight junctions (occluding junctions)
What is the difference between an exocrine gland and an endocrine gland? Give an
example of each.
Endocrine - Sweat, Saliva
Endocrine- diretcly into blood stream
Where does transitional epithelium occur and what is its function?
The function of transitional epithelium cells is to protect the urinary system against the toxic effects of urine. Additionally, transitional epithelium cells stretch to accommodate the volume of the bladder and other organs when they fill with liquid
How might connective tissues be classified?
Matrix is similar to hyaline cartilage but less firm. Thick collagen fibers predominate. Hard calcified matrix containing many collagen fibers. … It is classified as connective tissue because it develops from mesenchyme and consists of blood cells surrounded by a nonliving matrix.
What is mesenchyme and what cells does it form?
Mesenchymal cells are able to develop into the tissues of the lymphatic and circulatory systems, as well as connective tissues throughout the body, such as bone and cartilage. A malignant cancer of mesenchymal cells is a type of sarcoma.
Why is collagen strong?
Collagen is a fibrous protein consisting of three polypeptide chains wound around each other. Each of the three chains is a coil itself. Hydrogen bonds form between these coils, which are around 1000 amino acids in length, which gives the structure strength
How is collagen made?
Collagen is generally synthesized by cell types derived from mesenchyme, e.g., fibroblasts, osteoblasts, chondroblasts and smooth muscle cells. The collagen of the basal lamina of the basement membrane is synthesized by epithelial cells of various types.
What aminos are needed for collagen?
Lysine / Proline
Discuss the structure of ‘ground substance’ in relation to its properties
The ‘ground substance’ of extracellular matrix is an amorphous gelatinous material. It is transparent, colourless, and fills the spaces between fibres and cells. It actually consists of large molecules called glycosoaminoglycans (GAGs) which link together to form even larger molecules called proteoglycans.
What are the differences in structure and location of different types of loose
connective tissue and dense connective tissues
Loose (areolar connective tissue) is the most abundant form of collagenous connective tissue. It occurs in small, elongated bundles separated by regions that contain ground substance.
Dense connective tissue is enriched in collagen fibers with little ground substance. If the closely packed bundles of fibers are located in one direction, it is called regular; if oriented in multiple directions, it is referred to as irregular. An example of regular dense connective tissue is that of tendons; an example of irregular dense connective tissue is that of the dermis.
What are ‘GAG’s?
Glycosaminoglycans (GAGs) or mucopolysaccharides are long unbranched polysaccharides consisting of a repeating disaccharide unit. Found in connective tissue
Function of adipose tissue?
loose connective tissue composed of adipocytes. Its main role is to store energy in the form of fat, although it also cushions and insulates the body.
Describe the different types of cells found in connective tissues.
fibroblasts, mast cells, plasma cells, macrophages, adipocytes, and leukocytes.
How does connective tissue differ from epithelial tissue?
Connective has blood vessels and transports nutrients
Epitheleal - such as linign lungs and kidneys tkaes form a basement membrane
State three properties of neurons.
Propagation of nerve impulses,
Secretion of Neurotransmitters over synapse
Neuroplasticity/modifiability.
What is meant by the term ‘motor neuron’?
a nerve cell forming part of a pathway along which impulses pass from the brain or spinal cord to a muscle or gland.
What is the difference between axons and dendrons?
dendrites carry signals from the pre-synaptic cell to the cell body. Axons carry signals away from the cell body toward the post-synaptic cell
What is the difference between a nerve fibre and a nerve?
Nerve fibers in both CNS and PNS, Nerves only in PNS.
Nerves are bundle sof Axons.
Nerve fibers are individual fibers.,
How do nerve cells get their nutrients?
Neurons obtain virtually all of their nutrition via aerobic metabolism of glucose - Glucose and 02
How does the peripheral (PNS) and central nervous systems (CNS) differ? How are
they similar?
The peripheral nervous system or PNS contains the nerves, which leave the brain and the spinal cord and travel to certain areas of the body.
The peripheral nervous system’s main job is to send information gathered by the body’s sensory receptors to the CNS as quickly as possible.
What is the autonomic nervous system? What are its major divisions and what do
they do?
The autonomic nervous system also has two divisions: the sympathetic division and the parasympathetic division. These two divisions have antagonistic (opposing) effects on the internal organs they innervate (send nerves to = act on). The sympathetic division, shown at the left, is the emergency system.
