part 3

• What is homeostasis?


  Homeostasis is the body's way of keeping its internal environment stable even when the outside world changes.
• why is homeostasis important?

  Homeostasis is important because it ensures that cells and organs work properly, maintaining health and function.
• how does the body maintain homeostasis?

  the body maintains homeostasis through various systems that regulate temperature, pH levels, hydration and other vital conditions.
• What are some examples of homeostasis in the body?

  Examples include regulating body temperature, blood sugar levels, and the balance of water and salts.
• what role do feedback loops play in homeostasis?

  feedback loops help the body respond to changes by either enhancing (positive feedback) or reducing (negative feedback) the initial change.
• what is an example of a negative feedback loop in homeostasis?

  An example is how the body lowers blood sugar levels by releasing insulin
• what happens if homeostasis is not maintained?

  If homeostasis is not maintained, it can lead to diseases or disorders, as the body's internal environment becomes unbalanced
• What is the Extracellular fluid (ECF)?

  ECF is the fluid outside the cells that serves as a buffer between cells and the external environment, helping maintain homeostasis.
• What is the internal environment of multicellular animals called?

  The internal environment is called the Extracellular fluid (ECF), which surrounds the cells.
• What is the law of mass balance in homeostasis?

  The law of mass balance states that if the amount of a substance in the body is to remain constant, any gain must be offset by equal loss.
• How does the body maintain water balance?

  Water loss through sweat and urine must be balanced by water intake from external sources and metabolic water production.
• what are the two main output options for maintaining mass balance?

  The two main options are excreting the material (e.g., urine, feces, CO2) or converting the substance to a different one through metabolism.
• What is the difference between steady state and equilibrium in homeostasis?

  Steady state refers to the dynamic stability of the body's compartments, while equilibrium implies a static, unchanging state. Homeostasis aims to maintain a dynamic steady state.
• What is local control in homeostasis?

  Local control is the simplest form of control, restricted to the tissues or cells involved, such as when oxygen concentration in a tissue decreases and nearby blood vessels dilate to increase oxygen supply.
• What is reflex control in homeostasis?

  Reflex control involves long-distance signaling and is used for widespread changes in the body, such maintaining blood pressure through the nervous or endocrine systems.
• What can cause a disruption in homeostasis leading to disease?

  External changes like toxic chemicals, or physical trauma, and internal changes like abnormal cell growth or autoimmune disorders, can disrupt homeostasis and lead to disease.
• What is the importance of constancy in the internal environment?

  Most cells are not tolerant to changes in their surroundings, so maintaining a stable internal environment is crucial for their function.
• What is the role of control mechanisms in homeostasis?

  Control mechanisms help keep regulated variables within a normal range, involving either local or long-distance reflex control.
• What are the main components of the cell membrane?

  The cell membrane is made up of a double layer of phospholipids with embedded proteins, carbohydrates, and cholesterol.
• What is the function of the extracellular fluid (ECF)?


  The ECF surrounds cells and helps maintain a stable environment for cellular function by transporting nutrients, gases, and wastes.
• What is osmotic equilibrium?

  Osmotic equilibrium occurs when the concentration of solutes is equal on both sides of a membrane, allowing water to move freely to balance the concentrations.
• What is osmotic pressure?


  Osmotic pressure is the pressure required to prevent water from moving across a membrane due to osmosis.
• What is the role of aquaporin channels?

  Aquaporin channels facilitate the movement of water across cell membranes, helping to maintain osmotic balance.
• how do adipose tissue and skeletal muscle differ in water content?

  Adipose tissue has low water content (mostly lipids), while skeletal muscle has high water content (75%)
• What is dynamic steady state?

  A dynamic steady state means the internal environment remains stable even though materials constantly move between compartments.
• What are the four main functions of the cell membrane?

  • Physical isolation
  • Regulation of exchange with the environment
  • Communication between the cell and its environment
  • Structural support
• What is meant by chemical and electrical disequilibrium?

  It refers to the unequal distribution of ions and molecules across cell membranes, resulting in differences in charge and chemical composition between compartments.
• What is the function of glial cells?

  Glial cells support and protect neurons, provide nutrients, maintain homeostasis, and form myelin
• What is the role of astrocytes?

  Astrocytes help maintain the blood-brain barrier, provide nutrients, and regulate the extracellular fluid in the brain
• What is the purpose of the glycocalyx?

  The glycocalyx is a protective coat formed by glycoproteins on the cell surface, involved in cell recognition and interaction.
• What are neurons?


  Neurons are nerve cells that transmit electrical signals in the body. They consist of a cell body, dendrite (receive signals), and an axon (sends signals).
• What is an action potential 


  An action potential is a sudden change in electrical charge across neuron's membrane, allowing it to transmit a signal along the axon.
• Synapse


  Is the gap between two neurons where signals are transmitted from one neuron to another using neurotransmitters.
• What are neurotransmitters?


  Neurotransmitters are chemicals released by neurons to send signals across synapses to other neurons or muscles.
• Myelin sheath?


  The myelin sheath is a protective layer around axons that helps speed up transmission of electrical signals along the neuron.
• Resting membrane potential


  is the electrical charge difference across the neuron's membrane when it is not transmitting a signal, typically around -70 mV.
• Depolarization


  When the neuron's membrane potential becomes less negative (more positive), moving towards zero, which is the first step in generating an action potential.
• Repolarization


  Repolarization is the process of the neuron's membrane returning to its resting potential after depolarization, becoming more negative again
• Hyperpolarization?


  Hyperpolarization is when the neuron's membrane potential becomes more negative than its resting potential, usually following repolarization.
• refractory period


  The refractory period is the time after an action potential during which a neuron is unable to fire another action potential. This ensures signals only travel in one direction.