Coordination: Nervous System, Muscle Contraction, Hormones, and Photoperiodism

Flashcards covering the organization of the nervous system, action potential, synapse, muscle contraction, hormone types and mechanisms, and photoperiodism.

The __ nervous system consists of the brain and spinal cord.

Processes many different kinds of incoming sensory information, and consists of the brain and spinal cord.

The __ nervous system consists of all nervous tissue outside the CNS and includes sensory and motor neurons.

Consists of all nervous tissue outside the CNS. It consists of sensory (afferent) neurons which transmit impulses from receptor to CNS, and motor (efferent) neurons which transmit impulses from CNS to effectors (muscles/glands/ endocrine cells).

__ is the difference in electrical charge across a cell's plasma membrane.

The difference in electrical charge (voltage) across a cell’s plasma membrane due to the differential distribution of ions. A cell that exhibits this is said to be polarized.

__ is the electrical potential difference across the plasma membrane of an excitable cell under resting condition.

Electrical potential difference (voltage) that exists across the plasma membrane of an excitable cell under resting condition. In neurons, it measures about -70 mV.

Regarding ion distribution in resting potential, the concentration of K+ is outside the neuron and inside the neuron.

Outside neuron: ↓ [K+], ↑ [Na+]. Inside neuron: ↑ [K+], ↓ [Na+]

In resting potential, the plasma membrane is more permeable to __ ions.

Plasma membrane has more passive K+ channels than passive Na+ channels, making the axon membrane more permeable to K+.

In resting potential, most __ inside the cell are not free to leave.

Most anions (protein) inside the cell are not free to leave and Plasma membrane is impermeable to negatively charge Cl-.

The sodium-potassium pump pumps Na+ out of the cell and K+ into the cell.

Pump 3 Na+ out of the cell and 2 K+ into the cell against their concentration gradient.

A __ ion channel opens or closes in response to a particular stimulus.

A transmembrane protein channel that opens or closes in response to a particular stimulus.

An __ is an electrical signal that propagates along the membrane of a neuron.

An electrical signal that propagates along the membrane of a neuron or other excitable cell as a nongraded (all-or-none) depolarization.

The series of stages for the generation of action potential involve: __.

Resting state, Depolarization, Rising phase of the action potential, Falling phase of the action potential (Repolarization), and Undershoot (Hyperpolarization).

During the depolarization phase, the presence of a stimulus opens some __ channels.

Presence of stimulus opens some voltage-gated Na+ channels.Na+ diffuse/inflow into the axon. Membrane potential becomes slightly depolarized. Voltage-gated K+ channels remain closed.

During the rising phase of action potential, voltage changes trigger more __ channels to open.

Voltage changes triggers more voltage-gated Na+ channels to open. More Na+ diffuse/ Na+ influx into the axon, causing the membrane to depolarize further. Membrane potential inside the axon (axoplasm) becomes more positive.

During the falling phase, channels open and channels become inactive.

Voltage-gated Na+ channels inactive (inactivation channel closed). Most voltage-gated K+ channels open. K+ diffuse out of the axon. Causes the inside of the membrane become negative again.

During undershoot, voltage-gated __ channels close slowly, leading to hyperpolarization.

Voltage-gated K+ channels close slowly. Excess K+ diffuse out/ efflux the axon. Inside of the axon membrane/ axoplasm becomes more negative than resting potential.

During depolarization in action potential propagation, the affected area of the membrane becomes more __.

The affected area of the membrane is more positive with the adjacent area still at resting potential. The difference in potentials between active and resting membrane regions causes Na+ to flow between them in a local current.

An action potential is triggered only if depolarization is above the __ level.

An action potential is triggered only if the depolarization of the membrane is above the threshold level. Strong stimuli produce action potentials more rapidly.

The __ is the brief recovery phase after a neuron's response during which it cannot respond to another stimulus.

The brief recovery phase after the response of a neuron during which it cannot respond to another stimulus.

__ is the period when the axon cannot transmit another action potential, no matter how great the stimulus is.

During the millisecond or so in which axon cannot transmit another action potential no matter how great the stimulus is.

During the __ refractory period, the axon can transmit impulses only with a larger-than-normal stimulus.

The axon can transmit impulses but only by a larger-than-normal stimulus/ with higher threshold (less negative) values.

The speed of conduction depends on what two factors?

Presence of myelin sheath and Diameter of axon.

In myelinated axons, action potentials 'jump' from one node of Ranvier to another, a process known as __.

Myelinated neurons conduct action potentials faster than non-myelinated neurons. Depolarization only occurs at the nodes of Ranvier.The action potential will ‘jump’ from one node of Ranvier to another known as saltatory conduction which speed up the impulse transmission.

__ axons propagate action potentials faster due to less resistance to local current flow.

Larger-diameter axons propagate action potentials faster than smaller ones due less resistance to the flow of local current.

A __ is the junction where a neuron communicates with another cell.

The junction where a neuron communicates with another cell across a narrow gap via a neurotransmitter or an electrical coupling.

The __ is the narrow gap between the pre- and postsynaptic cells.

A narrow gap which separates the postsynaptic cell from the presynaptic cell ≈ 20 nm wide.

The synaptic knob contains numerous __ to supply energy.

Contains numerous mitochondria to supply energy for the activities of neurons, and membrane-bound synaptic vesicles that contain neurotransmitter

A __ neuron carries a nerve impulse towards a synapse.

A nerve cell that carries a nerve impulse towards a synapse.

A __ contains neurotransmitters like acetylcholine and norepinephrine.

Vesicle containing neurotransmitter, such as ACETYLCHOLINE and NOREPINEPHRINE.

In impulse transmission across the synapse, action potentials arrive at the __ of the presynaptic neuron.

Action potentials arrive at axon terminal (synaptic knob) of presynaptic neuron and presynaptic membrane undergo depolarization.

Depolarization triggers the opening of __ channels in the presynaptic neuron.

Depolarization trigger the opening of voltage-gated Ca2+ channels. Presynaptic neuron membrane becomes more permeable to Ca2+ and Ca2+ from extracellular fluid diffuse into synaptic knob.

The influx of __ triggers synaptic vesicles to release neurotransmitters.

The diffusion of Ca2+ trigger synaptic vesicles to fuse with presynaptic membrane and release the neurotransmitter into synaptic cleft via exocytosis.

Neurotransmitter binding to receptors opens __ channels on the postsynaptic membrane.

Binding of neurotransmitter to the receptors causes the ligand-gated ion channels to open on postsynaptic membrane and Na+ diffuse into postsynaptic neuron.

After an action potential at the postsynaptic membrane is produced, neurotransmitters are removed by __.

Reuptake of neurotransmitter or Enzymatic degradation by specific enzymes in the synaptic cleft.

Transmission of impulse along the axon neurotransmitters and is transmitted .

Occurs along the axon (myelinated or non- myelinated) while Synapse occurs between two neurons. Along the axon there is no neurotransmitter/chemical messenger, the impulse is electrically transmitted, involves both voltage-gated Na+ and K+ channel, and is faster.

Cocaine primarily affects the nerve cells in the brain's __ system.

Cocaine affects the nerve cells at the brain’s limbic system (pleasure pathway of the brain).

Cocaine blocks the __ transporter, preventing dopamine reuptake.

Cocaine enters synaptic cleft and blocks the dopamine transporter at presynaptic membrane, preventing the reuptake of dopamine.

Addiction build, thus more and more __ is needed for the addict to experience the pleasurable effects.

Cocaine.

__ is a severe mental disturbance with psychotic episodes characterized by hallucinations and delusions caused by excess of dopamine.

A severe mental disturbance characterized by psychotic episodes in which patients have a distorted perception of reality. Typically experience hallucinations and delusions.

Parkinson's disease is caused by the death of neurons that release __ in the midbrain.

The death of neurons in the midbrain that normally release dopamine at synapses in the basal nuclei.

The __ is the junction between a motor neuron and muscle fiber.

The junction between a motor neuron and muscle fiber where the neurotransmitter involves is acetylcholine.

The synaptic terminal contains __ that contain neurotransmitter.

Has synaptic vesicles that contain neurotransmitter.

Each extensively folded sarcolemma on the motor end plate is called and has .

Each extensively folded sarcolemma on the motor end plate is called junctional folds and Has ligand-gated ion channels.

Each myofibril is composed of what two types of filaments?

Thin filaments (actin) and Thick filaments (myosin)

Each sarcomere consist of bundles of and .

Myosin (thick filament) and Actin (thin filament).

The components of a sarcomere include the H zone, A band, I band, , and .

H zone – consists only of thick filament, A band – consist both thick and thin filament overlap, I band – consist only of thin filaments, Z line – hold the thin filament, and M line – hold the thick filaments.

Each actin molecule has a __ that binds to the myosin head.

Each actin has a myosin-binding site that binds to the myosin head during muscle contraction.

During contraction, the and decrease in length.

During contraction the actin filament move inwards towards the center of the sarcomere, the I band and H zone decrease in length.

When the muscle relaxes, the actin filaments slide back to their __.

The actin filaments slide back to their original position, the muscle relaxes.

Steroidal or amino acid–based molecules released to the blood that act as chemical messengers to regulate specific body functions (Human Anatomy & Physiology 12th Edition).

Definition of hormones

The three main types of hormones are __.

Steroid hormone, Amine, and Peptide.

In gene activation, mRNA binds with __ to undergo translation, forming a specific protein.

mRNA binds with ribosome to undergo translation forming specific protein / enzyme that can carry out a specific response to the hormonal signal.

In the second messenger system, __ acts as a second messenger activating protein kinase A.

cAMP act as second messenger which activates protein kinase A.Activated protein kinase A phosphorylate various other protein by cascade effect – trigger cell response.

The two forms of phytochrome are __.

Pfr (phytochrome which absorbs far red light at 730 nm) and Pr (phytochrome which absorbs red light with a peak at 660 nm).

_is the active form of phytochrome, triggering or inhibiting responses of flowering.

Pfr.

Low-Level Pfr stimulates the conversion of __ into florigen that promotes flowering.

Inactive hormones precursor.

High level of __ stimulate the conversion of Inactive hormones precursor into florigen that promotes flowering..

Pfr.