Body Fluids Lecture 1 Flashcards
What is homeostasis?
relative stability of the “milieu intérieur”
What is the milieu interieur?
Internal environment that surrounds the tissues and cells
External Environment
Environment ouside of the organism. It is the physical, chemical, social conditions that surround an organism
Internal environment
The environment that surrounds cells and tissues (relatively constant under conditions of health) also called the “millieu interior”
What is homeostasis in regards to the internal and external environments?
Human body regulates it’s internal environment in response to the external environment (ex. when temp or blood pressure increase internal environment will adjust)
What is the point of all functional activities in the body?
To maintain homeostasis
Is the internal environments different from the external enviornment?
Yes, it is vastly different
What is the most abundant body fluid?
Water
What occurs in body water?
- Solutes are dissolved
- Metabolic reactions take place
Why do metabolic reactions take place in water?
Lots of metabolic reactions produce heat, since water has a high specific heat capacity(requires a lot of energy to increase it by one degree) it acts as a good temperature buffer
Give four other roles of water in the body?
- Regulates body temp.
- Moistens tissues such as those in mouth, eyes and nose
- Protects body organs and tissues
- Lubricates joints
- Helps prevent constipation
- Lessens the burden on the lidneys and liver by flushing out waste products
- Helps dissolve minerals and other nutrients to make them accesible to the body
- Carries oxygen and nutrients to cells
Percent of water in skin
70%
Percent of water in muscle
75%
Percent of water in Heart, Liver, Brain and Kidney
70-80%
Percent of water in bone
25%
Percent of water in Fat (adipose tissue)
10%
What is the dryest type of tissue?
Fat
What happens if someone has a lot of adipose tissue?
They will have a lower total water content
What happens if someone has very little fat(adipose tissue)?
They will have a higher total water content
What is lean body mass?
Overall weight of a person minus the weight from their body fat
When comparing water to lean body mass what is the difference between a fat and skinny person?
The difference between a skinny and fat person becomes insignificant when comparing total body water as a proportion to lean body mass
What is the physiological reference individual?
21-year-old, white male, 70-kg
Why are all standards made for a 21 year old white male?
Standard reference values were computed in the 1920s by medical students who fit this criteria
Newborns body water content
Have 75% water, as adipose tissue is added babies water content decreases
How does puberty affect body water content between males and females?
Females - At puberty female sex hormone estrogen leads to subcutaneous fat in the breast/buttocks. This results in females being drier than males
Do males/females have the same water content prior to puberty?
Yes
How does aging affect water content?
Both sexes become drier as they age due to more adipose tissue and loss of muscle mass (muscles are replaced with connective tissue which is significantly drier)
How to calculate the absolute amount of water?
(Weight of person times % of water) divided by 100 equals absolute amount of water
Why is knowing body water necessary?
Need to know it in order to administer water-soluble medication
Is body water a Dynamic Steady state?
Yes
What is a dynamic steady state?
Water is constantly flowing in(drinking water)/out(peeing) there will always be a constant amount of water but it won’t be the same water
What is water balance?
When intake of water is equal to output
How do we intake water?
-Orally through fluid
-Orally through solids(food)
- Oxidative water from metabolism
What is an insensible output?
Losses that we cannot feel