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Flashcards in Lecture 1 Deck (31):
1

Themes of Physiology

Physical-chemical basis of body function
structure function relationships
energy use
homeostasis
integration

2

Physical-chemical Basis of body function

focus on MECHANISM: how the body works

3

Structure-function relationships

Body function depends on structure at all levels of biological organization
Cell basic unit of life
organism is the most highly integrated level

4

Energy Use

life requires a continuous input of chemical energy
body cells obtain energy

5

Homeostasis

maintenance of relatively constant internal conditions in the body
central principle of physiology

6

Integration

Body systems are functionally connected and work together

7

Integration of organ systems
(what do they do and what controls them, role of circulatory system)

OS work together to support body function
OS share a common internal environment; some organ systems have surfaces that contact the external environment
Nervous system and endocrine system control other organ systems
circulatory system transports and exchanges substances w/ other organ systems

8

External environment

Includes lumen of hollow organs that open to outside
Part of external environment
respiratory, digestive, urinary, reproductive

9

Extracellular fluid (ECF)

Internal environment
contains interstitial fluid (11L) and blood plasma(3L)
1/3 of total body water
major solutes: Na+, Cl-, some organic molecules
Functions as buffer between cells and external environment

10

ECF Is high in _ and low in _

high in Na+
Low in K+

11

Intracellular fluid (ICF)

2/3 of total body water
major solutes K+ and organic molecules A-
contained in trillion of cells

12

Intracellular fluid is high in _ and low in _

low Na+
high K+

13

Plasma Membrane

separates ICF and ECF
maintains different composition of ICF and ECF by selective permeability and molecular transport
prevents easy movement of ions

14

Epithelium

Forms boundary between internal environment (ECF) and external environment
A protective barrier
exchanges surfaces
functions in absorption, secretion, gas exchange

15

Free Surface

faces external environment (or lumen of hallow organs)

16

Law of Mass balance (steady state process)

open system, INPUT=OUTPUT to maintain a constant level
Example: input (food+drink+metabolism) = output (urine+feces+evaporation)

17

What is required to maintain homeostasis

ENERGY
ex. Na-k pump uses ATP to maintain [Na+] and [K+] of ICF and ECF
ex. cellular respiration

18

Why is the ECF regulated

to maintain suitable conditions for cells

19

7 essential variables

body temp, arterial blood pressure, pH, Po2, Pco2, blood, plasma osmolarity

20

Body Temperature

37*C

21

Arterial Blood Pressure

120/75 mm Hg
Mean = 90 mm Hg (millimeters of mercury)

22

Arterial pH

7.4, slightly alkaline

23

Arterial Po2

P= pressure
pressure of o2
100 mm Hg

24

Arterial Pco2

carbon dioxide pressure
40 mm Hg

25

Blood [glucose]

when fasting
90 mg/dL

26

Plasma osmolarity

290 mOsm (concentration of all dissolved substances in plasma)

27

Control of homeostasis

Negative feedback control maintains homeostasis
usually regulated by nervous and endocrine systems

28

set point

optimum value/normal value
variable are regulated around a set point

29

Direction of response

corrective response is in the opposite direction during negative feedback
ex: heat gain means heat loss to decrease body temp
heat loss means heat gain to increase body temp

30

If you are too Hot what happens

the skin are hypothalamus detect that you are too hot (sensors)
sweat glands release sweat and vasodialation occurs
(effectors)
body temperature decrease (response)

31

Positive feedback

non-homeostatic
results in rapid change of variable
Not very common

Ex. LH surge triggers ovulation