Physiology Resit Flashcards
What is an action potential?
A rapid, temporary change in the electrical charge of a neuron’s membrane, allowing nerve signal transmission.
What is the resting membrane potential in mV?
-70mV
What maintains the resting membrane potential?
Na⁺/K⁺ ATPase pump (3 Na⁺ out, 2 K⁺ in)
What happens during depolarization?
Voltage-gated Na⁺ channels open, Na⁺ rushes in, and the inside of the neuron becomes more positive.
What is the threshold voltage for depolarization?
-55mV
What is the peak voltage reached during depolarization?
+30mV
What occurs during repolarization?
Na⁺ channels close, K⁺ channels open, and K⁺ moves out of the cell.
What is the membrane potential during hyperpolarization?
-80mV
What leads to hyperpolarization?
K⁺ channels close slowly, causing the membrane to be more negative than the resting potential.
How is the resting potential restored after an action potential?
Na⁺/K⁺ ATPase restores the balance.
Name and explain the function of 5 organelles.
- Nucleus – Stores genetic material (DNA) and regulates cell activities.
- Mitochondria – Powerhouse of the cell; produces ATP via aerobic respiration.
- Ribosomes – Synthesizes proteins (found on the rough ER or floating in cytoplasm).
- Endoplasmic Reticulum (ER)
* Rough ER – Helps in protein synthesis (studded with ribosomes).
* Smooth ER – Synthesizes lipids and detoxifies substances. - Golgi Apparatus – Modifies, sorts, and packages proteins and lipids.
Name and explain the function of 5 organelles.
- Lysosomes – Breaks down waste and cellular debris.
- Peroxisomes – Detoxifies harmful substances, including hydrogen peroxide.
- Cytoskeleton – Provides structure and aids in intracellular transport.
- Centrosome (Centrioles) – Important in cell division (helps organize spindle fibers).
- Plasma Membrane – Controls the movement of substances in and out of the cell.
State the name of the connective tissue that is essential for the structure of the human body.
Collagen – It provides strength, support, and structure to tissues, including skin, bones, and tendons.
How many organ systems are there?
11 organ systems:
1. Integumentary (skin, hair, nails)
2. Skeletal (bones, joints)
3. Muscular (muscles, tendons)
4. Nervous (brain, spinal cord, nerves)
5. Endocrine (hormone-producing glands)
6. Cardiovascular (heart, blood vessels)
7. Lymphatic/Immune (lymph nodes, spleen, white blood cells)
8. Respiratory (lungs, trachea)
9. Digestive (stomach, intestines, liver)
10. Urinary (kidneys, bladder)
11. Reproductive (ovaries/testes)
Is blood a tissue? If yes, what kind?
Yes, blood is a connective tissue. It consists of cells (RBCs, WBCs, platelets) suspended in plasma, functioning in transport, immunity, and clotting.
Explain why epithelial tissues can be more prone to tumour developments.
- High Cell Turnover – Epithelial cells constantly divide, increasing the chance of mutations.
- Exposure to Carcinogens – They line organs and are exposed to harmful substances (UV rays, smoke).
- Basement Membrane Dependency – If they break through, tumors can spread (metastasis).
What initiates the chemical synapse process?
An action potential reaches the presynaptic terminal of a neuron
What happens when the action potential arrives at the axon terminal?
Voltage-gated calcium channels open
What causes calcium ions to enter the presynaptic neuron?
The concentration gradient
What triggers synaptic vesicles to fuse with the presynaptic membrane?
The rise in intracellular Ca²⁺ levels
What are the neurotransmitters that can be released during vesicle fusion?
- Glutamate
- GABA
- Acetylcholine
What occurs after neurotransmitters are released into the synaptic cleft?
They diffuse toward the postsynaptic membrane
What happens when neurotransmitters bind to receptors on the postsynaptic membrane?
Ion channel activation occurs
What can occur in the postsynaptic neuron depending on the neurotransmitter and receptor type?
- Excitation (depolarization and possible action potential)
- Inhibition (hyperpolarization and reduced likelihood of firing)
