CHAPTER 1
Differences in Extracellular (1/3 of body fluid) and Intracellular Fluids (2/3 of body fluid)
extracellular fluid (aka internal environment of the body) (outside cells) contains:
– large amounts of sodium, chloride, and bicarbonate ions
– plus nutrients for the cells (oxygen, glucose, fatty acids, and amino acids)
– carbon dioxide (transported from the cells to the lungs to be excreted)
– cellular waste products (transported to the kidneys for excretion)
intracellular fluid (inside cells) contains:
large amounts of potassium, magnesium, and phosphate ions
homeostasis- the maintenance of nearly constant conditions in the internal environment.
Disease- a state of disrupted homeostasis.
EXTRACELLULAR FLUID TRANSPORT AND MIXING SYSTEM—THE BLOOD CIRCULATORY
SYSTEM
Extracellular fluid is transported through the body in two stages:
1- movement of blood through the body in the blood vessels.
2- movement of fluid between the blood capillaries and the intercellular spaces between the
tissue cells.
– As blood passes through blood capillaries, continual exchange of extracellular fluid occurs
between the plasma portion of the blood and the interstitial fluid that fills the intercellular
spaces.
ORIGIN OF NUTRIENTS IN THE EXTRACELLULAR FLUID
Respiratory System:
– The blood picks up oxygen in alveoli, thus acquiring the oxygen needed by cells.
– The membrane between the alveoli and the lumen of the pulmonary capillaries, the
alveolar membrane, is only 0.4 to 2.0 micrometers thick
– oxygen rapidly diffuses by molecular motion through this membrane into the blood.
Gastrointestinal Tract:
, Here different dissolved nutrients, including carbohydrates, fatty acids, and amino acids, are
absorbed from ingested food into the extracellular fluid of the blood.
Liver and Other Organs That Perform Primarily Metabolic Functions:
– The liver changes the chemical compositions of many of these substances to more usable
forms, and other tissues of the body—fat cells,
– gastrointestinal mucosa, kidneys, and endocrine glands help modify the absorbed
substances or store them until they are needed.
– The liver also eliminates certain waste products produced in the body and toxic
substances that are ingested.
Musculoskeletal System:
Provides mobility to- obtain the foods required for nutrition
-for protection against adverse surroundings
REGULATION OF BODY FUNCTIONS
Nervous System.
The nervous system is composed of three major parts:
– the sensory input portion,
– the central nervous system (or integrative portion),
– the motor output portion.
Sensory receptors detect the state of the body and its surroundings.
Appropriate signals are then transmitted through the motor output portion of the nervous
system to carry out one’s desires.
autonomic system operates at a subconscious level and controls many functions of
internal organs
Hormone Systems
endocrine glands- organs and tissues that secrete hormones.
Hormones are transported in the extracellular fluid to other parts of the body to help
regulate cellular function
– thyroid hormone increases the rates of most chemical reactions in all cells
– Insulin controls glucose metabolism,
– adrenocortical hormones control sodium and potassium ions and protein metabolism,
Differences in Extracellular (1/3 of body fluid) and Intracellular Fluids (2/3 of body fluid)
extracellular fluid (aka internal environment of the body) (outside cells) contains:
– large amounts of sodium, chloride, and bicarbonate ions
– plus nutrients for the cells (oxygen, glucose, fatty acids, and amino acids)
– carbon dioxide (transported from the cells to the lungs to be excreted)
– cellular waste products (transported to the kidneys for excretion)
intracellular fluid (inside cells) contains:
large amounts of potassium, magnesium, and phosphate ions
homeostasis- the maintenance of nearly constant conditions in the internal environment.
Disease- a state of disrupted homeostasis.
EXTRACELLULAR FLUID TRANSPORT AND MIXING SYSTEM—THE BLOOD CIRCULATORY
SYSTEM
Extracellular fluid is transported through the body in two stages:
1- movement of blood through the body in the blood vessels.
2- movement of fluid between the blood capillaries and the intercellular spaces between the
tissue cells.
– As blood passes through blood capillaries, continual exchange of extracellular fluid occurs
between the plasma portion of the blood and the interstitial fluid that fills the intercellular
spaces.
ORIGIN OF NUTRIENTS IN THE EXTRACELLULAR FLUID
Respiratory System:
– The blood picks up oxygen in alveoli, thus acquiring the oxygen needed by cells.
– The membrane between the alveoli and the lumen of the pulmonary capillaries, the
alveolar membrane, is only 0.4 to 2.0 micrometers thick
– oxygen rapidly diffuses by molecular motion through this membrane into the blood.
Gastrointestinal Tract:
, Here different dissolved nutrients, including carbohydrates, fatty acids, and amino acids, are
absorbed from ingested food into the extracellular fluid of the blood.
Liver and Other Organs That Perform Primarily Metabolic Functions:
– The liver changes the chemical compositions of many of these substances to more usable
forms, and other tissues of the body—fat cells,
– gastrointestinal mucosa, kidneys, and endocrine glands help modify the absorbed
substances or store them until they are needed.
– The liver also eliminates certain waste products produced in the body and toxic
substances that are ingested.
Musculoskeletal System:
Provides mobility to- obtain the foods required for nutrition
-for protection against adverse surroundings
REGULATION OF BODY FUNCTIONS
Nervous System.
The nervous system is composed of three major parts:
– the sensory input portion,
– the central nervous system (or integrative portion),
– the motor output portion.
Sensory receptors detect the state of the body and its surroundings.
Appropriate signals are then transmitted through the motor output portion of the nervous
system to carry out one’s desires.
autonomic system operates at a subconscious level and controls many functions of
internal organs
Hormone Systems
endocrine glands- organs and tissues that secrete hormones.
Hormones are transported in the extracellular fluid to other parts of the body to help
regulate cellular function
– thyroid hormone increases the rates of most chemical reactions in all cells
– Insulin controls glucose metabolism,
– adrenocortical hormones control sodium and potassium ions and protein metabolism,
