NEUR301 Test 4

Which type of muscle(s) have extensive electrical coupling?

• Skeletal muscle

• Cardiac muscle

• Smooth muscle

• No muscles have electrical coupling

Answer explanation

The term electrical coupling refers to presence of gap junctions where electrical activity in one cell can spread to the other without employing synapses

Thin filaments are made up of…

Answer explanation

Thick filaments are made up of myosin

Together they make a sarcomere

Which ion binds to troponin?

• Mg²⁺

• Ca²⁺

• Na⁺

• K⁺

Answer explanation

Troponin is bound to tropomyosin and is a calcium sensor. Once calcium binds to troponin it causes a conformational change in tropomyosin. This exposes actin’s surface which myosin binds to and forms a cross-bridge

Within a muscle motor unit size...

• Can vary

• Is always consistent within a muscle but can differ between muscles

• Is always consistent within and between muscles

• None of the above

Answer explanation

Motor unit is set of muscle fibers innervated by a single motor neuron, together with the motor neuron itself

Almost all muscles are arranged in ___ pairs

Answer explanation

A single muscle can only exert force in one direction meaning it cannot re-lengthen itself, therefore, they usually are arranged in pairs where contraction of one muscle lengthens the other.

Which channels are responsible for the funny current?

• Cl^- channels

• Mg²⁺ channels

• HCN channels

• DAG channels

Answer explanation

HCN or hyperpolarization-activated cyclic nucleotide-gated (HCN) channels open during undershoot, allowing cations to flow into the cell and depolarize it again.

Which neurotransmitter decreases funny current strength?

Through which nerve is most of the information from the internal organs to the CNS transmitted?

• Trigeminal nerve

• Vagus nerve

• Abducens nerve

• Accessory nerve

What receptors monitor blood pressure and are located on carotid arteries and heart?

Which hormone release can circumventricular osmoreceptors trigger?

• Vasopressin

• Oxytocin

• Somatostatin

• Glucagon

Answer explanation

Vasopressin is an antidiuretic hormone. It reduces urine production by triggering the release of water from the kidneys and allowing it to reenter body tissue