Electrolytes - normal body composition

Question 1

What are electrolytes?

Answer 1

minerals in your body that have an electric charge

Question 2

Where are electrolytes found?

Answer 2

in blood, urine, tissues, and other body fluids

Question 3

How do electrolytes maintain homeostasis?

Answer 3

by balancing water content and the body’s acid/base (pH) level

Question 4

What are electrolytes obtained from a balanced diet?

Answer 4

sodium, calcium, potassium, chloride, phosphate and magnesium

Question 5

What do electrolytes ensure healthy functioning of?

Answer 5

nerves, muscles, the heart, and the brain

Question 6

What is the process of homeostasis?

Answer 6

to stay alive, an organism keeping its internal environment relatively constant and different from its external environment

Question 7

Where are the concentrations of ions inside a cell of any organism kept?

Answer 7

at a different level from the concentrations outside

Question 8

How does a cell maintain these internal and external concentrations?

Answer 8

by importing some substances and exporting others

Question 9

What do electrolytes carry?

Answer 9

a charge and are essential for life

Question 10

What is higher extracellularly, sodium or potassium?

Answer 10

sodium, potassium is higher inside the cell

Question 11

What are other important ions?

Answer 11

Cl-, Ca2+, H+

Question 12

What are differences in concentration important for?

Answer 12

cellular function, for example, concentration gradient enables healthy function of electrically active cells such as nerve cells

Question 13

Fluid compartments: percentage total fluid?

Answer 13

60% body weight

Question 14

Fluid compartments: percentage intracellular fluid?

Answer 14

67% body fluid

Question 15

Fluid compartments: percentage extracellular fluid?

Answer 15

33% body fluid

Question 16

Fluid compartments: Volume intravascular component?

Answer 16

3 litres plasma
5 litres blood

Question 17

What do electrolytes determine?

Answer 17

the distribution between intra- and extra- cellular compartments

Question 18

How is water inputted?

Answer 18

drink (1500), in food (800), metabolism of food (200)

Question 19

How is water outputted?

Answer 19

urine (1500), skin and respiratory tract (800), stool (200)

Question 20

What is renin?

Answer 20

an enzyme produced in the kidneys in response to sympathetic stimulation and altered blood flow.

Question 21

What does renin do?

Answer 21

it converts angiotensinogen to angiotensin I

Question 22

How is angiotensin I converted to angiotensin II?

Answer 22

in the lungs by angiotensin converting enzyme (ACE)

Question 23

What does the conversion of angiotensin I to angiotensin II do?

Answer 23

• stimulates adrenal cortex to produce the hormone aldosterone
• activates pump in the distal renal tubule leading to reabsorption of Na+ and water from the urine in exchange for K+ and H+ ions

Question 24

How is water balance mainly controlled by?

Answer 24

Na+

Question 25

What does an increased plasma Na+ cause?

Answer 25

thirst -> release of antidiuretic hormone (ADH) from the posterior pituitary -> increases the passive water reabsorption from renal collecting ducts

Question 26

Where does ion transport go on?

Answer 26

- acid secretion in stomach - absorption in GI tract - muscle function - neuronal function - renal-hepatic systems

Question 27

What are clinical features of electrolyte imbalance?

Answer 27

- low body sodium - water excess - high body sodium - water deficiency

Question 28

What does low body sodium cause?

Answer 28

cellular over-hydration; confusion, fits

Question 29

What does water excess cause?

Answer 29

hypertension, cardiac failure, oedema, anorexia, nausea, muscle weakness

Question 30

What does high body sodium cause?

Answer 30

cellular dehydration; thirst, confusion, coma

Question 31

What does water deficiency cause?

Answer 31

hypotension, low pulse volume, decreased skin turgor, peripheral vasoconstriction, tachycardia, raised plasma protein

Question 32

What is dehydration?

Answer 32

when your body loses more fluid than you take in

Question 33

What is upset when the normal water content of your body is reduced?

Answer 33

the balance of minerals (salts and sugar) in your body, which affects the way that it functions

Question 34

What does water do?

Answer 34

it makes up 2/3 of healthy human body, lubricating joints and eyes, aids digestion, flushes out waste and keeps skin healthy

Question 35

What are some of the early warning signs of dehydration?

Answer 35

- feeling thirsty and light-headed - having dark coloured, strong-smelling urine - passing urine less often than usual

Question 36

When may a baby be dehydrated?

Answer 36

- have a sunken soft spot (fontanelle) on their head - have few or no tears when they cry - have fewer wet nappies - are drowsy (their body is affected even when they lose a small amount of fluid

Question 37

Why should you not give too much water solely to infants for rehydration?

Answer 37

it may exacerbate the problem by diluting electrolytes/minerals further

Question 38

What is recommended for rehydration in infants?

Answer 38

squash/oral rehydration solutions in small amounts