SFB AQ1

How many organ systems comprise the human body?

11

Explain systems integration using the example of thermoregulation in response to being cold.

In response to a cold stimulus, thermoregulation involves multiple body systems working together to conserve and generate heat.

Temperature sensors in the skin (integumentary system) and brain (nervous system) detect the drop in temperature and send nerve signals to the hypothalamus (nervous system), which has the setpoint for body temperature.

The nervous system triggers vasoconstriction to reduce blood flow to the skin (muscular system and cardiovascular system), minimizing heat loss.

It also initiates shivering, which generates heat through muscle contractions (muscular system).

The endocrine system releases thyroid hormone and adrenaline to increase metabolic rate and heat production (endocrine system).

These coordinated responses help maintain core body temperature by conserving heat and producing additional warmth, illustrating how multiple systems integrate to maintain homeostasis.

Explain what an emergent property is

An emergent property is a complex function or behavior that arises from the coordinated interaction of multiple individual systems and cannot be predicted by looking at each system separately.

As Aristotle said, “the whole is more than the sum of its parts,” meaning that when systems work together, new properties emerge that do not exist in any single part alone.

Many individuals erroneously say that the heart is located inside the pericardial cavity. How would you correctly describe the heart in relation to the pericardial cavity?

The pericardial cavity surrounds the heart and contains serous fluid.

A cardiothoracic surgeon cracks open a patient’s thoracic cavity. The surgeon needs access to the heart and, therefore, needs to cut through the pericardial sac with her scalpel.

List the proper sequence of the pericardial layers she must cut through to get to the surface of the heart.

Fibrous pericardium → serous pericardium (parietal pericardial membrane → visceral pericardial membrane).

How many layers will she cut through until serous fluid starts to ooze out?

2 (fibrous pericardium and parietal pericardial membrane).

Three different cavities surround three major organs of the human body; the heart, the lungs, and the viscera. What are these three cavities named?

Heart - pericardial cavity

Lungs - pleural cavity

Viscera - peritoneal cavity

What is a mesentery?

A mesentery is a double layer of visceral peritoneum. (which is in the abdominiopelvic cavity)

It contains connective tissue, vasculature and nerve fibers.

During general surgery, a hack surgeon made a mistake and cut a major mesentery. What future complications may this patient experience if it’s not repaired?

Their gut won’t move food along as well, because the nerves that tell the muscles to squeeze and push (peristalsis) aren’t working.

They would not be able to absorb vital nutrients to keep themselves alive or deliver oxygen/nutrients to the small intestines to keep them alive.

Their intestines would have impaired structural support within the abdominal cavity as well.

Total body water is approximately 35-40 liters. Where is most of this water located in the body?

The intracellular compartment (i.e., the inside of your cells – intracellular fluid (ICF)).

What are the approximate volumes of each fluid compartment within the human body (interstitial fluid (ISF), extracellular fluid (ECF), intracellular fluid (ICF), and intravascular fluid (IVF))?

Plasma (IVF) = Men 3 L; Women 2 L

Interstitial fluid (ISF) = Men 11 L; Women 8 L

Extracellular fluid (ECF) = Men 14 L; Women 10 L

Intracellular fluid (ICF) = 28 L ; Women 20 L

What literally is extracellular fluid (ECF)?

·      ECF = ISF + IVF.

Extracellular fluid = Interstitial fluid + Intravascular fluid (Plasma) fluid

Explain how the fluid compartments would change, in volume, if someone with hypertension (high blood pressure) was directed by their physician to decrease their salt intake.

The solute concentration of the plasma would decrease. This would cause water to leave the bloodstream and enter the ISF. CONFUSED #7

An alien was discovered to vasoconstrict in response to an increase in its body temperature. Is this response human-like?

In a human, an increase in body temperature leads to vasodilation. Therefore, this response in the alien is not human-like.

What type of feedback does this represent and how do you know?

This response is positive feedback because it works to increase conditions away from homeostasis.

As the body temperature of the alien increases, vasoconstriction occurs which brings blood away from the surface of the skin in order to conserve heat.

This will increase its total body temperature, which continues this process.

You spent the last 12 years living in Antarctica where the temperature ranges from -60ºF to 10ºF. You travel to Florida for spring break. As soon as you step out of the airport you instantly feel a heat wave of the 90ºF weather and your skin feels hot. Your body senses this change and sends signals to your brain, nerve cells and skin.

In attempts to get your body temperature back to normal, you notice your forehead is wet with sweat. What process is your body going through to prevent you from overheating?

Negative feedback

In response to an acute hyperglycemic episode (blood glucose >100 mg/dl), what is the

Sensory information?

Receptor?

Control Center?

Afferent Info?

Efferent Info?

Sensory information = Glucose

Receptor = The pancreatic beta cell

Control Center = The pancreatic beta cell

Afferent Info = Downstream signaling pathways inside the beta cell.

Efferent Info = Insulin

What are the effector cells?

Fat cells (adipocytes)

Liver cells (hepatocytes)

Skeletal muscle cells (myocytes).

What do each of these effector cells do to drop blood glucose levels?

Adipocytes (fat cells) remove glucose from the blood and convert it to glycerol to eventually form triglycerides (lipogenesis).

Hepatocytes (hepatocytes) and myocytes (Skeletal muscle cells) remove glucose from the blood and store it as glycogen (glycogenesis).

Which of these cells is/are insulin-sensitive that require insulin stimulation for them to uptake glucose?

·      Adipocyte (fat cell) and skeletal muscle cell (myocyte).

How do these cells uptake glucose from the ISF?

Facilitated diffusion via glucose transporters (GLUTs).

In response to an acute hypoglycemic episode (blood glucose <70 mg/dl), what is the

Sensory information?

Receptor?

Control Center?

Afferent Info?

Efferent Info?

Sensory information = Glucose

Receptor = The pancreatic alpha cell

Control Center = The pancreatic alpha cell

Afferent Info = Downstream signaling pathways inside the alpha cell

Efferent Info = Glucagon

What is the effector cell?

Hepatocytes (Liver Cell)

What does the effector cell do to increase blood glucose?

Hepatocytes release glucose into the blood by way of

Breaking down glycogen into glucose monomers (glycogenolysis) and

By making glucose from amino acids (gluconeogenesis).

What does metformin do for a type II diabetic?

Metformin inhibits gluconeogenesis and thereby reduces hepatic output of glucose into the blood. This helps regulate their blood glucose levels.