88 terms

BIO test 2

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Ectoderm:
produces epithelial and nervous tissue
Endoderm:
produces only epithelial tissue and specifically linings of respiratory and digestive tracts
Mesoderm:
produces muscle, connective, and epithelial tissues of circulatory system, skeletal system, and parts of the excretory system
Positive feedback:
Maintains initial stimulus or condition
ex. oxytocin causing increased uterine contraction in mammals
Ectotherms:
Use external sources of heat
ex. Fish, amphibians, and reptiles , Behavioral modifications are important for regulating body temperature
Endotherms:
Use metabolism to generate body heat
ex. mammals,Typically maintain their temperatures above the ambient temperature
homeotherms
maintain stable temperature (can vary and is not necessarily much higher than surroundings) (can increase metabolism to produce heat)
ex. birds
Negative feedback:
Reverses the initial stimulus or condition
blastocyst
pluripotent
gastrula
multipotent; endoderm, mesoderm, ectoderm
epithelial tissue
Forms exterior and interior linings of organs
functions: Protection, secretion, absorption, erosion
connective tissue
produces non-cellular matrix
functions: support, cushion, transport
(3 types)
- loose (between skins and organs)
- Dense (tendons, ligaments, sheathing around muscles
- special (cartilage, bone blood)
muscle tissue
3 types:
- smooth: involuntary/automatic (blood vessels, digestive tract)
- skeletal: voluntary/somatic (attach to bones)
- cardiac: involuntary/automatic (in heart only)
tissue that is the framework for all other tissues in organ structure
connective
nerve tissues
composed of specialized neurons to conduct electromagnetic signals (impulses)
3 types: sensory, motor, interneurons
central nervous system
the command center; includes brain and spinal cord
peripheral nervous system
collects info and carries out responses; includes sensory neurons and motor neurons
sensory neurons
carry impulses to the central nervous system
motor neurons
carry impulses from the CNS to effectors
autonomic pathways
consist of sympathetic and parasympathetic divisions
parasympathetic pathways
divert activities to "housekeeping" processes such as digestion. slows overall body function (tune out, turn off)
ex. calming, conserving energy, slow heart rate, digesting
sympathetic pathways
diverts activities to overall heightened function during times of heightened awareness (tune-in, turn on)
ex. stress situations (heart rate sped up, dilate pupils)
neurotransmitters
nerves that communicate electrically by impulses
somatic nerves
primarily act on voluntary (conscious) activities such as skeletal muscles (by motor neurons). carry signals from skin, skeletal muscles and tendons.
autonomic nerves
involuntary and primarily act on visceral functions. Carry signals from respiratory and GI systems, cardiac muscles, and glands
spinal cord
conveys messages and controls some responses directly
reflexes
sudden, involuntary movements of muscles in response to a stimulus
ganglia
bundles of neurons that can integrate some sensory to motor functions
dendrites
get info from axons and receptors (receives messages from other cells)
axon
carries info to synapse; action potential
Neuroglia (Schwan cells):
wraps around axon and forms myelin sheath (which speeds up neural impulses)
cell-body
cells life-support center
axon terminus
form junctions with other cells
node of ranvier
gaps in myelin sheath which help conduct nerve impulses; saltatory transmission (action potentials from one node to next)
synapse
gap between 2 neurons- transfers info between 2; 3 parts: presynaptic membrane (at terminus), the postsynaptic membrane (dendrite and cell body), and space between (synaptic cleft) - release neurotransmitter
release of neurotransmitters
action potential changes membrane potential allowing for calcium to flow in because of diffusion; increased concentration on the inside causes vesicles to fuse with membrane and by diffusion, neurotransmitters are pushed out into synaptic cleft to bind with receptor on postsynaptic membrane
strength/duration/frequency of action potential
controls amount of neurotransmitters released
Action Potentials
An electrical difference exists across the axon plasma membrane.
Neurotransmitters
Chemicals ligands that convey the message across the synapse.
threshold potential
The level of depolarization needed to produce action
Caused by open and closing ion channels
Acetylcholine
Neuromuscular junction, exitory, depolarize
Amino acids (GABA)
inhibitory, hyperpolarize axon
Serotonin
regulation of sleep, emotional stress
Dopamine
released in areas of the brain controlling body movements + other areas
forebrain
divided further into the diencephalon and telencephalon.
cerebrum
center for association and learning.
three categories of receptors
mechanoreceptors, chemoreceptors, and energy-detecting receptors
4 steps of converting sensory transduction
1. Stimulation, 2. transduction, 3. transmission, and 4. interpretation.
sensory transduction
produces a graded receptor potential. A single potential or a sum of potentials may exceed a threshold to produce an action potential
mechanoreceptors
Pain receptors alert the body to damage or potential damage. Nociceptors (pain)
Tonic receptors
convey duration information. (action potentials slow-but-steady over the duration of stimulus)
phasic receptors
convey information on intensity and rate. (action potentials increase or diminish very quickly)
Proprioceptors
provide information about the relative position or movement of body parts and the degree of muscle stretching.
Baroreceptors (proprioceptors)
monitor blood pressure
mechanoreceptors
Ear structure and lateral line in fishes contain ______.
chemoreceptors
detects tastes and analyzes potential food.
Sour (pH) , Salty , Sweet, Bitter, Umami
tastebuds (which are on the tongues papillae) have 5 categories:
Smell, or olfaction
involves chemoreceptors located in the upper portion of the nasal passages. Their axons connect directly to the cerebral cortex. (can identify a vast number of complex molecules)
pupil
right enters through the
iris and associated ciliary muscle
light intensity controlled by the
the lens
focuses light on the retina
rod cells and cone cells
Vertebrate photoreceptors
rods
detect shades of gray
cones
used for visual acuity and color vision
retina
in the _____, photoreceptors synapse with bipolar cells, which in then synapse with ganglion cells. The ganglion cells send action potentials to the brain.
cerebral cortex
where visual processing takes place
fovea
a region of the retina responsible for high acuity, each cone cell is connected to a single bipolar cell/ganglion cell,
snakes
can detect infrared radiation (heat) due to the detection done by the pit organ
sharks and duck-billed platypuses
can detect electrical currents using electroreceptors
birds
can detect magnetic fields to navigate along
hormones
are signaling molecules carried by the blood and may have distant targets.
ex. Pancreas produces insulin and insulin receptors are on cells all around the body
paracrine
regulators that act locally
ex. A cell releases a signal and the cells adjacent to it receive the signal.
pheromones
released into the environment communicate between individuals of the same species
Norepinephrine
can act as both circulating hormones and neurotransmitters.
hormones
can be categorized as lipophilic or hydrophilic.
Lipophilic hormones
activate intracellular receptors.
hydrophilic hormones
activate receptors on target cell membranes
Anterior pituitary (adenohypophysis)
Releases regulatory factors that stimulate growth, and hormones that stimulate other endocrine glands; portal blood system carries regulatory factors from hypothalamus
Posterior pituitary
oxytocin & ADH; direct nerve connection from hypothalamus
thyroid gland
regulates basal metabolism and development. (thyroxine)
the adrenal gland
releases both protein (catecholamine) and steroid hormones.
Corticosteroids
(ex. cortisone) modulate some aspects of the immune response and maintain glucose homeostasis (ex. Cortisol).
Epinephrine and norepinephrine,
trigger "alarm" responses
pancreatic hormones
primary regulators of carbohydrate metabolism.
antagonistic hormones
insulin and glucagon.
melatonin
crucial to circadian cycles, can control the dispersion of pigment granules and the daily wake-sleep cycles.
The pineal gland
produces melatonin
skin
manufactures and secretes vitamin D