Veterinary Microscopic Anatomy (Histology) Lecture Notes

A comprehensive set of flashcards based on veterinary microscopic anatomy lecture notes, covering nervous tissue, integumentary system, and lymphoid system.

What is the main component of the nervous system?

The nervous tissue, which includes the brain, spinal cord, and peripheral nerves.

What are neurons responsible for?

Transmitting impulses.

What assists in the propagation of nerve impulses?

Neuroglial cells (glia).

What layer surrounds the axon of a neuron?

Myelin sheath.

What are the smaller gaps between segments of the myelin sheath called?

Nodes of Ranvier.

What is the function of Schwann cells?

They produce the myelin sheath in the peripheral nervous system.

What role do sensory neurons play?

They are responsible for sensory input.

What does the term 'integration' in nervous function refer to?

The process where sensory input combines to produce a certain output.

What are the parts of a neuron?

Cell body, dendrites, and axon.

What is the function of the axon?

It transmits the action potential signal to the next cell.

What is the 'axon hillock'?

The point of origin of the axon from the perikaryon.

What are synapses?

Specialized contacts between a presynaptic neuron and postsynaptic neuron.

What role do neurotransmitters play?

They mediate the transfer of information between neurons.

What is the most prominent excitatory neurotransmitter in the CNS?

L-glutamate.

What is the most significant inhibitory neurotransmitter?

Gamma-amino butyric acid (GABA).

What are astrocytes?

Star-shaped cells that provide support and maintain the composition of extracellular fluid.

What is the function of oligodendrocytes?

To form myelin sheath around axons in the CNS.

What is the function of microglia?

They proliferate and differentiate into phagocytic cells in response to tissue damage.

What do ependymal cells do?

Line the ventricles of the brain and the central canal of the spinal cord.

What do neurolemmocytes do?

Form the myelin sheath of axons in the peripheral nervous system.

How are neurons classified?

Based on the number of processes – unipolar, bipolar, and multipolar.

What is the primary function of the epidermis?

To protect the body from harmful influences in the environment.

What is the dermis composed of?

Connective tissue and develops from mesoderm.

What is the hypodermis?

A subcutaneous layer of loose connective tissue that binds skin to underlying structures.

What are the appendages of the skin?

Hair, nails, sweat glands, and sebaceous glands.

What characterizes the stratum corneum?

Composed of dead, keratinized cells that protect against fluid loss.

What glands produce sweat?

Sweat glands, which can be merocrine or apocrine.

What function do sebaceous glands have?

They secrete lipids into hair follicles.

What are the key differences between merocrine and apocrine glands?

Merocrine glands secrete watery sweat, while apocrine glands secrete milky, proteinaceous sweat.

What is the primary role of lymphatics?

To detect and inactivate foreign substances and return excess interstitial fluid to the bloodstream.

What is the structure of lymph nodes?

Composed of an outer cortex, paracortex, and inner medulla.

Where are T cells produced and matured?

In the thymus.

What role do B cells play in the immune system?

They turn into plasma cells to produce antibodies.

What major functions does the spleen perform?

Immunologic filtration of blood, activation of lymphocytes, and removal of old red blood cells.

What does the stroma of lymphoid organs consist of?

Reticulin fibers, except in the thymus where it consists of epithelial reticular cell processes.

What is the purpose of the blood-thymus barrier?

To protect developing T-cells from exposure to circulating antigens.

What characterizes primary lymphoid organs?

They are where lymphocytes arise and become immunocompetent.

How do T and B cell precursors differ in their maturation process?

B cells mature in the bone marrow, while T cells migrate to the thymus for maturation.

What do peripheral lymphoid organs primarily do?

Trap antigens and initiate immune responses.

What are secondary lymphoid organs comprised of?

Lymphoid follicles and diffuse lymphoid tissue.

What is the structure of the white pulp in the spleen?

Contains periarteriolar lymphatic sheaths and splenic follicles.

What are the components of the red pulp in the spleen?

Splenic sinuses and splenic cords.

What is the function of the tonsils?

To form aggregates of lymphoid follicles to intercept pathogens.

How does the dermis respond to tension during incisions?

Healing occurs faster when incisions are made parallel to lines of tension.

What function does keratinization serve in the skin?

It protects the underlying tissues from damage and water loss.

How do melanocytes contribute to skin pigmentation?

They produce melanin, which protects against UV damage.

What is unique about pseudounipolar neurons?

They originate as bipolar neurons during development but function with one process.

What are the different layers of the epidermis?

Stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale.

What cells are found in the dermis?

Fibroblasts, macrophages, and various immune cells.

Describe the role of myoepithelial cells in sweat glands.

They aid in the contraction of secretory cells to expel sweat.

What do T-lymphocytes do upon contact with an antigen?

They migrate to regional lymph nodes to initiate an immune response.

What is the cellular arrangement of lymphoid follicles?

Composed of small, dark, mature lymphocytes surrounding a germinal center.

What role does the hypodermis play in the skin?

Anchors the skin to underlying structures and provides insulation.

Where is the stratum granulosum located?

Above the stratum spinosum and below the stratum lucidum.

What is the appearance of sebaceous glands?

Simple and branched glands located around hair follicles.

What is the main component of the lymphatic fluid?

Lymphocytes, proteins, and sometimes bacteria.

How is lymph fluid formed?

When interstitial fluid seeps into lymphatic vessels.