Midterm 2 Flashcards
Examples of excitatory neurotransmitters
glutamate, aspartate, acetylcholine
Examples of inhibitory neurotransmitters
GABA, glycine
Which neurotransmitters can exert excitatory and inhibitory effects?
dopamine. serotonin
What do excitatory neurotransmitters do?
lower the postsynaptic membrane potential to increase firing rate (EPSP)
What do inhibitory neurotransmitters do?
stabilize or raise the postsynaptic potential to decrease firing rate (IPSP)
agonist neuromodulator
mimics action of neurotransmitter by binding to receptor
antagonist neuromodulator
blocks action of neurotransmitter by binding to receptor
facilitation neuromodulator
enhances effect of neurotransmitter by its increased concentration in the synaptic cleft, slower degradation, or slower reuptake resulting in greater response in the postsynaptic cell
inhibition neuromodulator
reduces effect of neurotransmitter by its decreased concentration in the synaptic cleft, faster degradation, or faster reuptake resulting in a lesser response in the postsynaptic cell
neuromodulation
release of chemicals from cells that alter or regulate the response of neurons to neurotransmitters
neuromodulator function
molecules can have enabling or disabling effect on the response to the neurotransmitter by binding allosterically to the postsynaptic receptor
what are the two types of postsynaptic receptors that neurotransmitters bind to?
ionotropic (ion channels)
metabotropic
main classes of neurotransmitters
acetylcholine (Ach)
biogenic amines (catecholamines, indolamines)
amino acids
neuropeptides
what are catecholamines synthesized from?
tyrosine
what are indolamines synthesized from?
histidine (ex. histidine) or tryptophan (ex. serotonin)
ionotropic receptors
ligand-gated transmembrane ion channels that can open in response to a binding molecule
metabotropic receptors
non-channel transmembrane proteins where a series of events may open another ion channel or activate other molecules within the cell
nicotinic receptors are
ionotropic, excitatory
where are nicotinic receptors found
-somatic effector (skeletal muscle) at neuromuscular junctions in the somatic nervous system
-postganglionic neurons at their synapse with preganglionic neurons in the autonomic ganglia of the ANS
-spinal cord of CNS
muscarinic receptors are
metabotropic, either excitatory or inhibitory
muscarinic receptors are found in
-remainder of CNS (brain)
-autonomic effector (cardiac and smooth muscle, glands w cholinergic innervation) at its synapse with the postganglionic neuron in the ANS
what is Alzheimer’s disease associated with
degeneration of cholinergic neurons
-decreased amount of Ach
-loss of postsynaptic neurons that would have responded to it
monoamine oxidase (MAO) function
enzyme that degrades catecholamines
adrenergic receptor types
alpha adrenergic receptors (usually excitatory)
beta adrenergic receptors (usually inhibitory)
adrenergic receptors
G protein coupled receptors that are generally linked to a second messenger signal transduction pathway
what second messenger is associated with alpha adrenergic receptors
alpha1- Ca2+ ions
alpha2- cAMP
what second messenger is associated with beta adrenergic receptors
cAMP
effects of beta adrenergic receptor subclasses
beta1- activation increases heart rate and contractility
beta2- relaxes smooth muscle in lung bronchioles to allow more oxygen intake during exercise
sympathetic preganglionic fibers
always cholinergic
sympathetic postganglionic fibers
mostly adrenergic, a few cholinergic
parasympathetic preganglionic fibers
always cholinergic
parasympathetic postganglionic fibers
always cholinergic
where are indolamines found?
brain and spinal cord (CNS)
serotonin effects (inhibitory? excitatory?)
excitatory effect on muscle control and inhibitory effect on pathways that mediate sensation
when are serotonin levels lowest and highest?
lowest- sleep
highest- alertness
when are serotonin levels lowest and highest?
lowest- sleep
highest- alertness
serotonin function
regulating sleep, emotions, vomiting reflex, regulates cell growth, vascular smooth muscle cell contraction
Parkinson’s disease brain involvement
loss of dopamine-releasing neurons in the substantia nigra of the midbrain
Parkinson’s symptoms
persistent tremors, head nodding and pill rolling behaviors, forward bent walking posture, shuffling gait, stiff facial expressions, slow initiation and execution of movement
which neurotransmitter type is the most abundant?
amino acid
most common inhibitory neurotransmitter
GABA- dampens neural activity in the brain
Tissues
groups of cells and the surrounding external that serve a common function
3 primary germ layers
ectoderm, mesoderm, endoderm
Hypertrophy
increase in cell size while the number of cells within the tissue remain constant
hyperplasia
increase in the number of cells in a tissue
atrophy
reduction in cell size and/or the number of cells in a tissue
necrosis
refers to dead tissue and described as “necrotic” clinically
metaplasia
tissues that transform into another tissue type
dyplasia
abnormal tissue development, may eventually form a tumor or return to normal tissue
neoplasm
tumor
can be non-cancerous and localized (benign) or cancerous and invasive (malignant)
metastatic
malignant neoplasms that have spread to other parts of the body
components of H & E stains
hematoxylin and eosin
hematoxylin
basic stain that stains acidic/basophilic structures blue/purple
ex) nuclei, ribosome, DNA, rER
eosin
acidic stain that stains basic/acidophilic structures pink
ex) collagen fibers, cytoskeleton
functions of epithelial tissues
barrier/protection
absorption of nutrients/fluids
transport across epithelial layers
secretion of hormones, enzymes, mucous
function of microvilli
increase surface area, allowing for more absorption
where are cilia found?
respiratory tract, female reproductive tract
corneal endothelium shape
hexagonal to maximize surface area
how many layers does corneal endothelium have
single layer of flattened cells
simple cuboidal epithelium morphology
singly layer, polygon-shaped
simple cuboidal epithelium function
secretion, absorption
where is simple cuboidal epithelium found?
kidney tubules, serves as the secretory unit of exocrine glands
simple columnar epithelium morphology
single layer, rectangular, nuclei often aligned basally
simple columnar epithelium function
absorption, secretion
simple columnar epithelium is found in
intestines (small, colon)
stomach
simple columnar epithelium with cilia found in
female reprodcutive tract, bronchi and bronchioles
stratified squamous epithelium morphology
flattened superficial cells
+/- keratinization
basal layers mitotically active, cells migrate towards the surface
stratified squamous epithelium function
protection, secretion
stratified squamous epithelium found in
mouth, esophagus, cornea, vagina (SSNK), epidermis (SSK)
stratified cuboidal epithelium function
absoption, secretion
stratified cuboidal epithelium found in
internal walls of the gland ducts
pseudostratified columnar epithelium morphology
-pseudo-multilayered, columnar shaped
-nuclei not aligned
-typically ciliated
pseudostratified columnar epithelium function
conduction, protetion, secretion
pseudostratified columnar epithelium found in
respiratory tract (“respiratory epithelium”)- trachea, bronchi
goblet cell morphology
modified columnsar epithelial cells, unicellular
goblet cell function
synthesize and secrete mucous that serves as a first line barrier of the immune system
goblet cells found in
scattered throughout many epithelial tissue linings
-respiratory tract
-ocular conjunctiva
-digestive tract
transitional epithelium morphology
stratified; cuboidal (non-distended) to squamous (distended)
transitional epithelium function
protection, distention
transitional epithelium found in
urinary tract (urinary epithelium)
exocrine glands type of secretion
mucous, serous (tears), seromucous (mucoid), sebaceous (meibum), sudoriferous (sweat)
merocrine (eccrine) secretion
-most common
-involves exocytosis (vesicles) as only secretory component released from glandular cells
-primarily protein products
apocrine secretion
membrane bound vesicles (apical)
primarily lipid-based products
apocrine secretion found in
breast and some sweat glands
used for thermoregulation, sexual attractant
types of growth in hyaline cartilage
interstitial growth, appositional growth
interstitial growth
from center, height
appositional growth
from edge, width
primary mechanism of cartilage growth
compact (cortical) bone
dense with organic ground substance and inorganic salts that also contain lacunae
cancellous bone
spongy; less dense and more porous
contains bone marrow
