Neuro Midterm

What are the three main types of neurons?

Pseudounipolar, bipolar, and multipolar.

How do pseudounipolar neurons differ from bipolar neurons?

Pseudounipolar neurons have an axon that splits into two branches, while bipolar neurons have one axon and one dendrite.

What neurotransmitter is secreted by cholinergic neurons?

Acetylcholine.

Which neurotransmitter has excitatory or inhibitory effects depending on the receptor?

norepinephrine

What is the primary neurotransmitter of the sympathetic nervous system?

Norepinephrine.

What are the main functions of the sympathetic nervous system?

Fight-or-flight response, increasing heart rate, and regulating arterial pressure.

Which nerve is responsible for decreasing heart rate in the parasympathetic nervous system?

The Vagus Nerve.

What is the function of prevertebral ganglia?

Relaying signals to visceral organs.

What type of neuron innervates extrafusal muscle fibers?

Alpha (α) motor neurons.

What is the role of afferent neurons?

They convey sensory information to the CNS.

What is the resting membrane potential (RMP) of skeletal muscle?

-90mV.

What is the resting membrane potential (RMP) of nerve cells?

-70mV.

Which muscle fiber type is slow-twitch and resistant to fatigue?

Type 1 fibers.

Which muscle fiber type primarily uses glycogen and glucose?

Type 2A fibers.

What ion links excitation to contraction in muscles?

Calcium ions.

In smooth muscle, what structure anchors thin filaments?

Dense bodies.

What triggers the power stroke in muscle contraction?

The release of ADP and Pi.

What is autorhythmicity in cardiac muscle?

The ability to generate its own impulses.

What is the function of the SA node?

It acts as the heart’s pacemaker.

What is the myocardium responsible for?

Contracting to pump blood.

Which structures in cardiac muscle contain gap junctions and desmosomes?

Intercalated discs.

How does smooth muscle differ from skeletal muscle in contraction?

It contracts via second messengers and is involuntary.

Why is smooth muscle stronger per cross-sectional area than skeletal muscle?

Because of its dense actin-myosin interactions.

What is a treatment option for myasthenia gravis?

Immunosuppressants.

What restores ion concentration gradients after an action potential?

The sodium-potassium pump.

What occurs during the absolute refractory period?

Sodium channels are inactivated.

What are graded potentials?

Local changes in membrane potential that can be summated.

What law do action potentials obey?

The all-or-none law.

How is electrical flow described in neural signaling?

As current.

Which energy system does not use calories and is active for short durations?

The phosphagen system.

How many ATP molecules are produced in glycolysis?

2 ATP.

What does the lactic acid system produce?

Hydrogen ions, but no ATP.

Which hormones affect smooth muscle?

Epinephrine, norepinephrine, and vasopressin.

What factor leads to vasodilation?

An increase in hydrogen ions.

What is the primary function of apocrine glands?

Secretion of thick, odoriferous substances.

What are the main components of the motor end plate?

Axon terminal, synaptic cleft, and synaptic gutter.

What enzyme breaks down acetylcholine in the synaptic cleft?

Cholinesterase.

Where is an electrical signal converted into a chemical signal?

At the axon terminal.

Who proposed the sliding filament theory?

A.F. Huxley and H.E. Huxley.

What is the main concept of the sliding filament theory?

Muscle contraction occurs as actin and myosin filaments slide past each other.

Which neurotransmitter is crucial for neuromuscular junction transmission?

Acetylcholine.

How do intercalated discs help cardiac muscle function?

They allow electrical signals to pass between cells rapidly.

What ion is necessary for neurotransmitter release at the synapse?

Calcium ions.

What part of a neuron transmits impulses away from the cell body?

The axon.

How does the parasympathetic nervous system affect digestion?

It enhances digestion by increasing gut motility.

Which type of muscle is striated and involuntary?

Cardiac muscle.

Why is the phosphagen system important for sprinting?

It provides immediate energy without requiring oxygen.

How do hormones like epinephrine affect blood vessels?

They can cause vasoconstriction or vasodilation, depending on the receptor type.

What distinguishes graded potentials from action potentials?

Graded potentials are local and summated, whereas action potentials are all-or-none.

What is the function of desmosomes in cardiac muscle?

They provide structural support by anchoring cells together.

What is the function of the nervous system?

To process and transmit information throughout the body.

What type of neuron is found in the dorsal root ganglion?

Pseudounipolar neurons.

Which part of a neuron receives incoming signals?

The dendrites.

Which division of the autonomic nervous system is responsible for the fight-or-flight response?

The sympathetic division.

Which neurotransmitter is primarily released by postganglionic sympathetic neurons?

Norepinephrine.

What is the primary function of the parasympathetic nervous system?

Rest and digest functions.

Where are prevertebral ganglia located?

In front of the vertebral column.

What part of the nervous system controls voluntary muscle movement?

The somatic nervous system.

What are the two main divisions of the autonomic nervous system?

The sympathetic and parasympathetic nervous systems.

Which type of neuron carries information from the CNS to muscles?

Motor (efferent) neurons.

What protein binds to calcium in muscle contraction?

Troponin.

What structure stores calcium in muscle cells?

The sarcoplasmic reticulum.

Which type of muscle fiber is most resistant to fatigue?

Type 1 (slow-twitch) fibers.

What is the primary function of Type 2A muscle fibers?

Fast oxidative glycolytic function using glycogen and glucose.

Which ion is necessary for muscle contraction to occur?

Calcium (Ca²⁺).

Which type of muscle contraction occurs when a muscle shortens under tension?

Concentric contraction.

Which type of contraction involves muscle lengthening under tension?

Eccentric contraction.

What is the neurotransmitter at the neuromuscular junction?

Acetylcholine (ACh).

What happens to actin and myosin during muscle contraction?

They slide past each other, shortening the sarcomere.

Which enzyme breaks down acetylcholine at the neuromuscular junction?

Acetylcholinesterase (cholinesterase).

How is cardiac muscle similar to skeletal muscle?

Both are striated and contain sarcomeres.

How is cardiac muscle different from skeletal muscle?

It is involuntary and has intercalated discs.

What is the primary pacemaker of the heart?

The SA (sinoatrial) node.

How does smooth muscle contract differently from skeletal muscle?

It contracts more slowly and via second messengers.

What connects cardiac muscle cells for electrical communication?

Gap junctions.

What anchors smooth muscle filaments?

Dense bodies.

Which structure allows cardiac muscle to contract as a single unit?

Intercalated discs.

What is the function of desmosomes in cardiac muscle?

To provide structural integrity.

Which nervous system primarily controls smooth muscle?

The autonomic nervous system.

What is a unique characteristic of smooth muscle compared to skeletal muscle?

It can maintain contraction for long periods with little energy use.

What is the role of the sodium-potassium pump?

To restore resting membrane potential by moving Na⁺ out and K⁺ in.

What is the threshold potential for initiating an action potential?

Approximately -55mV.

What happens during depolarization of a neuron?

Sodium (Na⁺) channels open, and Na⁺ enters the cell.

What happens during repolarization of a neuron?

Potassium (K⁺) channels open, and K⁺ leaves the cell.

What is the all-or-none principle?

An action potential either occurs completely or not at all.

What type of potential can summate: graded potential or action potential?

Graded potential.

What is saltatory conduction?

The jumping of action potentials between nodes of Ranvier in myelinated neurons.

What is the purpose of the absolute refractory period?

It prevents another action potential from occurring immediately.

How does myelination affect nerve conduction speed?

It increases conduction speed.

What is the difference between excitatory and inhibitory neurotransmitters?

Excitatory neurotransmitters depolarize the neuron; inhibitory neurotransmitters hyperpolarize it.

Which energy system provides immediate ATP?

The phosphagen system.

Which process breaks down glucose to produce ATP anaerobically?

Glycolysis.

How many ATP molecules are produced per glucose molecule in aerobic metabolism?

36-38 ATP.

What is the primary byproduct of anaerobic glycolysis?

Lactic acid.

Which energy system provides the most long-lasting ATP production?

The oxidative (aerobic) system.

What happens to lactic acid after intense exercise?

It is converted back into pyruvate or glucose in the liver.

Why is the phosphagen system important for high-intensity activities?

It provides ATP rapidly without using oxygen.

Which molecule is the primary fuel for long-duration, low-intensity exercise?

Fatty acids.

What is the main function of mitochondria in muscle cells?

ATP production via aerobic metabolism.

Which hormone plays a major role in glucose uptake into muscle cells?

Insulin.