Week 14 Lecture Quiz

What is innate immunity?

The ability to fight off pathogens without previous exposure to a certain pathogen.

List the types of innate immunity.

• Physical barriers

• Phagocytes

• Natural Killer Cells

• Inflammation

• Protective enzymes/proteins

What consists of the Central Nervous System?

Brain, Spinal Cord, and Interneurons

What consists of the Peripheral Nervous System (PNS)?

Nerves (cranial, spinal, peripheral, sensory, and motor)

Name the 2 types of nervous tissue.

Neurons and neuroglia

What are the three types of neurons?

Sensory, motor, and interneurons.

What do sensory neurons do?

Carry impulses to the CNS from the tissues.

What do interneurons do?

They carry impulses from one neuron to another within the CNS.

What do motor neurons do?

They carry impulses away from the CNS to muscles and glands.

What is the ratio of neuroglia to neurons?

9:1

What is the charge outside a nervous cell before an electrical impulse takes place?

Relatively positive charge

What is the charge inside a nervous cell before an electrical impulse takes place?

Relatively negative charge

What is an antigen?

Any foreign substance that triggers an immune response.

Where do B-Lymphocytes mature?

In the red bone marrow.

Where do T-Lymphocytes mature?

In the thymus.

What are antigen receptors?

Proteins on B and T cells that bind to specific antigens.

What is a pathogen?

A disease-causing agent.

What is adaptive immunity?

Which leukocytes are phagocytes?

Neutrophils and Monocytes (Macrophages)

Which leukocytes are natural killer cells?

B & T lymphocytes

How do B & T lymphocytes kill cells?

They kill virus-infected cells or body tumors by releasing chemicals (perforins) that cause apoptosis to the affected cell(s).

What are mast cells?

Specialized basophils release histamine and other chemicals (kinins) during inflammation and allergic reactions.

What is histamine?

A chemical that promotes inflammation, increases blood flow to tissues, and causes swelling and itching.

Name the processes of inflammation.

• Damage Occurs to tissues

• Mast cells are stimulated and releases histamines and kinins (granules)

• Blood capillaries to dilate, causing swelling, heat, redness, and pain

• Leukocytes can enter area of infection

• Neutrophils enter and begin to phagocytize pathogens.

• Monocytes enter tissues and become macrophages, capable of phagocytosis, and releases cytokines to attract more leukocytes

What is a lock and key defense?

Antigens fit specific receptors on B & T lymphocytes, triggering an immune response.

Describe what happens when an antigen binds with a B lymphocyte.

The binding triggers the B lymphocyte to undergo mitosis and differentiate into plasma cells, which produce antibodies specific to the antigen, and memory cells, that are similar to the mother cell and remain in the body to provide long-term immunity against future infections for that specific antigen.

What is the Antigen-Antibody Complex?

It is the result of the binding of an antibody to its specific antigen, forming a structure that helps neutralize pathogens and mark them for apoptosis by other immune cells. The plasma cell then kills itself (apoptosis)

What are schwann cells?

Neuronal cells that insulate, and wrap around axons, facilitating faster signal transmission.

What ion is most common outside a neuronal cell?

Sodium (Na+)

What ion is most common inside a neuronal cell?

Potassium (K+)

What is a Sodium-Potassium pump?

An integral protein that actively transports sodium out of and potassium into the cell, crucial for maintaining resting membrane potential.

Name the 4 stages of generating a nerve impulse.

Resting Potential, Depolarization, Repolarization, Refractory period.

How does the sodium-potassium pump move the ions in/out?

Active transport, against the concentration gradient

Describe the action potential stage of conducting a nerve impulse.

• Stimulation occurs, causing Na+ gates to open and Na+ flows into cell via “voltage gated channels” then making it impermeable to more Na+ ions.

• When Na+ threshold is reached, initiates action potential

• Stimulus causes the axon membrane to depolarize, reversing the membrane potential.

Define action potential is a neural cell.

A rapid change in membrane potential that occurs when a neural cell is stimulated, leading to the influx of sodium ions and the generation of an electrical impulse.

Describe the depolarization stage of conducting a nerve impulse.

The inside of the neural cell becomes net positively charged with the influx of Na+ ions, while the outside becomes net negatively charged.

Describe the Repolarization stage of conducting a nerve impulse.

K+ channels open, allowing them to flow out of the cell and returning the membrane potential to its resting state. (K+ is on outside, Na+ is on the inside)

Describe the Refractory Period stage of conducting a nerve impulse.

The time it takes after impulse for the neuron to recover and become capable of generating another action potential. During this period, the neuron has a much higher threshold, only being able to be triggered by an extreme stimuli.