Histology

Question 1

What are the four tissue types of the body?

Answer 1

epithelial, connective, muscular, and nervous tissue

Question 2

What is an endothelium? Where are endothelia located?

Answer 2

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

Question 3

. What is a basement membrane?

Answer 3

a thin, delicate membrane of protein fibres and mucopolysaccharides separating an epithelium from underlying tissue.

Question 4

What are the different types of cell junctions?

Answer 4

Adherens junctions, desmosomes and hemidesmosomes (anchoring junctions)

Gap junctions (communicating junction)

Tight junctions (occluding junctions)

Question 5

What is the difference between an exocrine gland and an endocrine gland? Give an
example of each.

Answer 5

Endocrine - Sweat, Saliva

Endocrine- diretcly into blood stream

Question 6

Where does transitional epithelium occur and what is its function?

Answer 6

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

Question 7

How might connective tissues be classified?

Answer 7

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.

Question 8

What is mesenchyme and what cells does it form?

Answer 8

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.

Question 9

Why is collagen strong?

Answer 9

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

Question 10

How is collagen made?

Answer 10

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.

Question 11

What aminos are needed for collagen?

Answer 11

Lysine / Proline

Question 12

Discuss the structure of ‘ground substance’ in relation to its properties

Answer 12

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.

Question 13

What are the differences in structure and location of different types of loose
connective tissue and dense connective tissues

Answer 13

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.

Question 14

What are ‘GAG’s?

Answer 14

Glycosaminoglycans (GAGs) or mucopolysaccharides are long unbranched polysaccharides consisting of a repeating disaccharide unit. Found in connective tissue

Question 15

Function of adipose tissue?

Answer 15

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.

Question 16

Describe the different types of cells found in connective tissues.

Answer 16

fibroblasts, mast cells, plasma cells, macrophages, adipocytes, and leukocytes.

Question 17

How does connective tissue differ from epithelial tissue?

Answer 17

Connective has blood vessels and transports nutrients

Epitheleal - such as linign lungs and kidneys tkaes form a basement membrane

Question 18

State three properties of neurons.

Answer 18

Propagation of nerve impulses,

Secretion of Neurotransmitters over synapse

Neuroplasticity/modifiability.

Question 19

What is meant by the term ‘motor neuron’?

Answer 19

a nerve cell forming part of a pathway along which impulses pass from the brain or spinal cord to a muscle or gland.

Question 20

What is the difference between axons and dendrons?

Answer 20

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

Question 21

What is the difference between a nerve fibre and a nerve?

Answer 21

Nerve fibers in both CNS and PNS, Nerves only in PNS.

Nerves are bundle sof Axons.
Nerve fibers are individual fibers.,

Question 22

How do nerve cells get their nutrients?

Answer 22

Neurons obtain virtually all of their nutrition via aerobic metabolism of glucose - Glucose and 02

Question 23

How does the peripheral (PNS) and central nervous systems (CNS) differ? How are
they similar?

Answer 23

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.

Question 24

What is the autonomic nervous system? What are its major divisions and what do
they do?

Answer 24

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.

Question 25

8. What are the functions of glial cells? How do they differ between the PNS and CNS?

Answer 25

surround neurons and hold them in place,
supply nutrients and oxygen to neurons,
to insulate one neuron from another,
destroy and remove the carcasses of dead neurons (

CNS supress repair

PNS promote repair.

Question 26

What is myelin? How does it support neural conductance?

Answer 26

a mixture of proteins and phospholipids forming a whitish insulating sheath around many nerve fibres, which increases the speed at which impulses are conducted.

by increasing the length constant and decreasing capacitance.

Question 27

What do transmission, transduction, and conductance mean?

Answer 27

Transmission - nerve signals via electircal changes along neuron

Signal transduction occurs when an extracellular signaling molecule activates a specific receptor located on the cell surface or inside the cell. In turn, this receptor triggers a biochemical chain of events inside the cell, eventually eliciting a response.

Conductance - speed of signal along axon

Question 28

What does the term ‘myogenic’ mean? When might we see myogenic control in
action?

Answer 28

originating in muscle tissue (rather than from nerve impulses).

The heart

Question 29

Differences between Smooth, Cradiac and Skeletal muscles

Answer 29

Smooth - supplied by autonomic nervous system and therefore they are involuntary in their action

Cardiac - They are striated like skeletal muscles but at the same time they are involuntary and have uninuclear cells like smooth muscles.

Skeletal - They are innervated by somatic nervous system and are therefore under voluntary control