Intro to Physiology

Question 1

LO #1: Define homeostasis.

Answer 1

Any self regulating process by which biological systems tend to maintain stability while adjusting to conditions that are optimal for survival. If homeostasis works, life goes on…if it doesn’t, death occurs.

Question 2

gradient

Answer 2

A difference in chemical concentration, charge, temperature or pressure between two points. Matter and energy tend to flow down gradients. For example, blood flows from higher pressure areas (aorta) to lower pressure areas (vena cavae). Resistance and magnitude of gradient affect flow.

Question 3

negative feedback loops

Answer 3

Majority of physical processes

Question 4

feedback loops

Answer 4

regulatory circuits that allow us to maintain homeostasis

Question 5

Heat Rash

Answer 5

prickly heat

Question 6

Heat Cramps

Answer 6

• severe, sometimes disabling cramps, that typically begin suddenly in the hands, calves or feet
• hard, tense muscles
• move to a cooler or air conditioned area
• sip water slowly until the cramps go away

Question 7

Heat Exhaustion

Answer 7

• heavy sweating
• weakness
• cold, pale, clammy skin
• fast, weak pulse
• nausea or vomiting
• fainting
• move to a cooler location
• lie down and loosen your clothing
• apply cool wet cloths to as much of your body as possible
• sip water
• if you have vomited and it continues, seek medical attention immediately

Question 8

Heat Stroke

Answer 8

• high body temp (above 103F)
• hot, red, dry or moist skin (blood needed for important organs)
• rapid and strong pulse
• possible unconsciousness
• call 911
• move the person to a cooler environment
• reduce the person’s body temperature with cool cloths or even a bath
• do NOT give fluids

Question 9

skin

Answer 9

protection, regulation, sensation

Question 10

CV system

Answer 10

pump system that allows blood with nutrients to get to all cells within the body, the heart and vessels allow transport of nutrients, oxygen and hormones to cells throughout the body as well as removal of metabolic wastes (carbon dioxide, nitrogenous wastes)

Question 11

Heat Stroke

Answer 11

• high body temp (above 103F)
• hot, red, dry or moist skin (blood needed for important organs)
• rapid and strong pulse
• possible unconsciousness
• call 911
• move the person to a cooler environment
• reduce the person’s body temperature with cool cloths or even a bath
• do NOT give fluids (not sure what is happening with body)

Question 12

CV system

Answer 12

pump system that allows blood with nutrients to get to all cells within the body, the heart and vessels allow transport of nutrients, oxygen and hormones to cells throughout the body as well as removal of metabolic wastes (carbon dioxide, nitrogenous wastes)
*heatstroke - increased heart rate as body keeps trying to increase evaporative cooling, low BP due to decreased blood volume (tremendous loss of fluids 2L/hr)

Question 13

skin

Answer 13

protection, regulation, sensation The skin has three main functions: protection, regulation and sensation. The skin provides
protection from: mechanical impacts and pressure, variations in temperature, micro-organisms,
radiation and chemicals. In terms of regulation, skin helps us regulate body temperature and
fluid balance. In terms of sensation, the skin contains an extensive network of nerve cells that
detect and relay changes in the environment.
* heatstroke -Liquids help to cool us down by allowing the body to produce sweat. However, liquids are
also necessary for bodily functions, such as keeping up blood pressure. You can lose large
amounts of body fluid in the form of sweat without noticing any effects, but at a certain point the
body will reserve the remaining fluid for vital functions and stop sweating. Sweat evaporates
more rapidly in dry weather, cooling the body more efficiently than in humid weather. When
working in humid conditions, the core temperature rises more rapidly. This is why weather
forecasts add a humidity factor or heat index to represent how you will actually feel outdoors

Question 14

CV system

Answer 14

pump system that allows blood with nutrients to get to all cells within the body, the heart and vessels allow transport of nutrients, oxygen and hormones to cells throughout the body as well as removal of metabolic wastes (carbon dioxide, nitrogenous wastes) Our pump system that allows blood with nutrients to get to all cells within the body.
The heart and vessels allow transport of nutrients, oxygen, and hormones to cells throughout
the body as well as removal of metabolic wastes (carbon dioxide, nitrogenous wastes). The
blood also contains the cells of the Immune System, which defend the body against foreign
microbes and toxins, and platelets, which play a role in coagulation. The combination of blood
and the vessels it moves through allows the cardiovascular system to play a role in temperature
regulation.
*heatstroke - increased heart rate as body keeps trying to increase evaporative cooling, low BP due to decreased blood volume (tremendous loss of fluids 2L/hr), the heart is also working
with reduced delivery of oxygen and nutrients. When this happens, the contractile cells of the
myocardium are unable to contract as forcefully, decreasing blood pressure and delivery of
blood to all organs. There is also the chance of changes in heart rhythm (arrhythmias), further
decreasing blood delivery

Question 15

respiratory system

Answer 15

involved in breathing, also called pulmonary ventilation The respiratory system is involved in breathing, also called pulmonary
ventilation. In pulmonary ventilation, air is inhaled through the nasal and oral cavities (the nose
and mouth). It moves through the pharynx, larynx, and trachea into the lungs. Then air is
exhaled, flowing back through the same pathway. Changes to the volume and air pressure in
the lungs trigger pulmonary ventilation. Inside the lungs, oxygen is exchanged for carbon
dioxide waste through the process called external respiration. This respiratory process takes
place through hundreds of millions of microscopic sacs called alveoli.
*heatstroke causes hypovolemia-less oxygen available, structure not fueled, pathogens let in = inflammation causing vasodilation leading to low blood volume
Less blood enters the pulmonary system (both for supplying the
structures of the lungs, and for gas transfer). Two things happen…first, the structures aren’t
receiving oxygen and nutrients needed to maintain their integrity, which can allow pathogens to
enter the blood stream. A person suffering from heat stroke will also increase respiratory rate,
which can lead to respiratory alkalosis. Over time, the cells of the respiratory system start to die
due to lack of oxygen and nutrients and there’s a switch to a metabolic acidosis

Question 16

renal system

Answer 16

kidneys remove liquid waste from the blood in the form of urine, keep a stable balance of salts and other substances in the blood, produce erythropoietin, a hormone that aids the formation of red blood cells The function of the kidneys is to remove liquid waste from the blood in the form
of urine; keep a stable balance of salts and other substances in the blood; and produce
erythropoietin, a hormone that aids the formation of red blood cells. It also senses and plays a
role in regulation of blood pressure.
*heatstroke - stops filtering, excess fluids and salts can also lead to hypertension due to fluid retention
Renal dysfunction in heat stroke can be caused by direct thermal injury, volume
depletion, or muscle cell breakdown (rhabodomyolysis). Dysfunctional kidneys lose the ability to
filter substrates, which can lead to fluid retention, increased blood pressure, and changes in
mental status.

Question 17

spleen

Answer 17

filter for blood as part of the immune system The spleen plays multiple supporting roles in the body. It acts as a filter for blood as
part of the immune system. Old red blood cells are removed from circulation in the spleen, and
platelets and white blood cells are stored there.
*heatstroke- stops filteringIf the cells of the spleen aren’t getting oxygen and nutrients, they will be unable to work
in the role of a filter (especially a place to remove red cells), and a person can become
jaundiced (due to increased circulating bilirubin from death of red cells not cleared from the
system). The spleen also acts as a secondary lymphoid structure and loss of function can be
associated with increased risk of infection

Question 18

GI tract

Answer 18

large muscular tube that extends from the mouth to the anus, where the movement of muscles, along with the release of hormones and enzymes, allows for the digestion of food The large, muscular tube that extends from the mouth to the anus, where the
movement of muscles, along with the release of hormones and enzymes, allows for the
digestion of food. Also called the alimentary canal or digestive tract.
*heatstroke - anoxia causes disruption of the GI barrier function, allowing escape of bacterial endotoxins into the gut tissue which leads to inflammation and sensation of cramping (visceral pain)Excessive heat exposure reduces intestinal integrity. Heat-stress causes blood to
move to the periphery in an attempt to maximize radiant heat dissipation, and this blood
redistribution is supported by vasoconstriction of the gastrointestinal tract. As a result, reduced
blood and nutrient flow leads to hypoxia at the intestinal epithelium, which ultimately
compromises intestinal integrity and function.

Question 19

LO #2: Describe a homeostatic process in the human body. Give specific examples of how all the organs work together.

Answer 19

A good example of homeostasis in medicine is the control of body temperature. In humans,
normal body temperatures hover around 37° C (98.6° F). However, various factors such as;
exposure to hot or cold, hormonal changes, changes in metabolic rate, or disease states can
cause body temperature to increase or decrease. Temperature regulation is controlled by the
hypothalamus in the brain. When changes in temperature are sensed, compensatory
mechanisms, which include shunting of blood to the skin or core, perspiration, or shivering
happen.

Question 20

LO #3: Describe how dysfunction in a single organ can lead to dysfunction of another organ.

Answer 20

The interconnectedness of the systems in the body.

Question 21

LO #4: List the steps associated in the loss of homeostasis in heat stroke.

Answer 21

Skin: Liquids help to cool us down by allowing the body to produce sweat. However, liquids are
also necessary for bodily functions, such as keeping up blood pressure. You can lose large
amounts of body fluid in the form of sweat without noticing any effects, but at a certain point the
body will reserve the remaining fluid for vital functions and stop sweating. Sweat evaporates
more rapidly in dry weather, cooling the body more efficiently than in humid weather. When
working in humid conditions, the core temperature rises more rapidly. This is why weather
forecasts add a humidity factor or heat index to represent how you will actually feel outdoors.

CV System: In an effort to decrease heat, the vessels (specifically the arterioles) nearest the
skin dilate…increasing heat dissipation. When this happens, there is less volume available to
meet the needs of other organs. In addition, when sweating, there was a decrease in total blood
volume due to fluid loss. The combination of vasodilation and decreased blood volume leads to
decreased blood pressure (the driving force of blood though the CV system). The heart must
then work harder to try and move blood through the body. However, the heart is also working
with reduced delivery of oxygen and nutrients. When this happens, the contractile cells of the
myocardium are unable to contract as forcefully, decreasing blood pressure and delivery of
blood to all organs. There is also the chance of changes in heart rhythm (arrhythmias), further
decreasing blood delivery.

Respiratory System: Less blood enters the pulmonary system (both for supplying the
structures of the lungs, and for gas transfer). Two things happen…first, the structures aren’t
receiving oxygen and nutrients needed to maintain their integrity, which can allow pathogens to
enter the blood stream. A person suffering from heat stroke will also increase respiratory rate,
which can lead to respiratory alkalosis. Over time, the cells of the respiratory system start to die
due to lack of oxygen and nutrients and there’s a switch to a metabolic acidosis

Renal System: Renal dysfunction in heat stroke can be caused by direct thermal injury, volume
depletion, or muscle cell breakdown (rhabodomyolysis). Dysfunctional kidneys lose the ability to
filter substrates, which can lead to fluid retention, increased blood pressure, and changes in
mental status.

Spleen: If the cells of the spleen aren’t getting oxygen and nutrients, they will be unable to work
in the role of a filter (especially a place to remove red cells), and a person can become
jaundiced (due to increased circulating bilirubin from death of red cells not cleared from the
system). The spleen also acts as a secondary lymphoid structure and loss of function can be
associated with increased risk of infection.

GI tract: Excessive heat exposure reduces intestinal integrity. Heat-stress causes blood to
move to the periphery in an attempt to maximize radiant heat dissipation, and this blood
redistribution is supported by vasoconstriction of the gastrointestinal tract. As a result, reduced
blood and nutrient flow leads to hypoxia at the intestinal epithelium, which ultimately
compromises intestinal integrity and function.