nervous and immune system

nervous system

divided into the cns and pns

central nervous system cns

brain and spinal cord

peripheral nervous system

cranial nerves, spinal nerves, autonomic nerves, ganglia

neurons

nervous system cells

soma: body

two processes: one axon, one or more dendrites

nucleus

dendrites

branch extensively(tiny trees) conduct nerve cells toward cell body

axon

extends out from body cell and ends in a terminal twig, carries impulses away from cell body

axon collaterals

axon side branches

nerve fibers

threadlike dendrites and axons

bundles of these are nerves

they are of different types

nuclei

groups of neuron cell bodies within the brain or spinal cord

those that are found outside are ganglia(ganglion)

tract

bundle of neuron fibers within the brain or spinal cord

neuroglia

specialized type of tissue that holds together and supports nerve cells

impulses

only pass in one direction

sensory/afferent neurons(ears, eyes, other sense organs)

to spinal cord and brain

motor or efferent

effectors- brain and spinal cord to muscles

connector

connected to other neurons

synapse

point at which an impulse is transmitted from one axon to another of one neuron to the dendrite of another

central nervous system

brain and spinal cord(cerebrospinal system)

meniges

3 membranes that envelop the cns

separating the brain and spinal cord from the body cavities

brain

contains over 100 billion neurons

spinal cord

flattened cylinder extending from medulla oblongata(hindbrain) to the lower lumbar vertebrae(enclosed in the vertebral column- protect from injury) and bathed in cerebrospinal fluid

sensations received by the sensory nerves are relayed to the spinal cord and transferred to the brain or motor nerves

peripheral system

stimulates proper effector organs in the body, muscles, or glands

all nerves and ganglia located outside of brain and spinal cord

cranial nerves

12 pairs(numbered I-XII)

spinal nerves

arise from spinal cord and emerge from vertebrae

immune system

consists of cells and chemicals that protect the body against invasion by foreign substances and maintains its general health

non specific immune mechanisms

inflammation- response to injury

defenses at the body surfaces

interferons- antiviral proteins(anti tumor activities)

integumentary system

physical and chemical barriers

chemical- skin

sweat, sebum, cerumen

respiratory system

mechanical and chemical barriers

mechanical- respiratory

ciliated mucous membranes filter incoming air of impurities

chemical- respiratory

mucus coats the walls of upper respiratory tract, entraps foreign material and has antiseptic properties

gastrointestinal tract

saliva and hydrochloric acid prevent many pathogens from multiplying

genitourinary tract

tears and urine:

wash out foreign substances from the body, limit growth of bacteria, kill certain organisms

phagocytosis

particulate matter is engulfed and destroyed by phagocytes(monocytes) and neutrophils

specific immune mechanisms

response of the defenses of the body to specific substances that are recognized as harmful: antigens

antigens

viruses, bacteria, parasites, etc

lymphocytes

leukocytes(wbcs) essential in specific immune defense

3 types: b-cells, t-cells, b/plasma/null cells

B cells

formed and mature in bone marrow, produce proteins called abs or immunoglobulins that respond to ags in the blood

humoral immunity

abs bind to the ags, preventing them from functioning and accelerating their destruction

B cells differentiate into(first response)

plasma cells

B cells differentiate into(long term immunity)

memory cells

T cells

formed in bone marrow

mature in thymus

cell mediated immunity

cytotoxic T cells(memory cells) and helper T cells

null cells

do not develop into memory cells

b/plamsa/helper t/cytotoxic T cells(that participated in attack on antigen die by

apoptosis

apoptosis

programmed cell death in which cell self-destructs(prevents immune defense from becoming too excessive)

protective immunity

passive & active

passive immunity

colostrum(first milk) and preformed antibodies(injected into animal)

active immunity

vaccination(administration of ag/vaccine to stimulate protective response against infectious agent)

natural infection w/microorganism

immune system weakness/deficiency

agammaglobulinemia, immunosuppression, opportunistic infections

agammaglobulinemia

animal has no abs circulating in blood

*highly susceptible to fatal infections

immunosupression

)induced by viruses, bacteria, parasites)

i.e. feline leukemia virus(FeLV)

feline immunodeficiency virus(FIV)

malignancies(lymphoma)

opportunistic infections

dx is not produced by organism that normally would produce dx

excessively strong immune system reactions

excessive inflammatory reactions: allergic reactions, atopy, anaphylaxis. autooimmune dx

allergic reactions

(hypersensitivity reaction)

from food, parasites(flea)

atopy

hypersensitivity reaction that involves skin

anaphylaxis

severe reaction to a foreign substance: vaccine or bee sting

*autoimmune dx

immune system cannot adequately distinguish between foreign abs and those of its own cells

body attacks its own cells and tissues

immune-mediated hemolytic anemia(IMHA)- rbcs are destroyed