1-Organization of Body and Homeostasis

go back and look at the different feedbakc pathways.

What is physiology?

the study of how living organisms function, how the body works

examples of functional anatomy

heart contracting to pump blood or stomach mixing to secrete enzymes

How does an increase of metabolic activity of a muscle lead to an increase in blood flow to that muscle

increase in metabolic activity of a muscle, it uses more O2 and nutrients, increase in blood flow provides the additional O2 and nutrients

pathophysiology

study of how and why normal function goes wrong

levels of organization in the body

cells → tissues → organ→ organ system

Cells

simplest structural units into which a multicellular organism can be divided and still retain life characteristics

5 functions of cells

1. cells exchange materials with their environment

2. they obtain energy from organic nutrients

3. they synthesize complex molecules

4. they can duplicate themselves

   1. they detect and respond to signals in their immediate environment

cell differentiation

specialization of cells into certain functions

steps to get to cel differentation

cell division then differentiate then specific cell types

4 differentiated cells

muscle cells, nerve cells, epithelial cells, connective tissue cells

muscle cells

myocytes- generate mechanical force and movement

types of muscle cells

skeletal cardiac and smooth muscle

nerve cells

neurons- specialized to initate and conduct electrical signals, control other cells activity

epithelial cells

located at the surface of the body or a hollow organ specialized for secretion and protection

connective tissue cell

connect anchor and support body structures

• loose connective tissue, dense connective tissue, blood, cartilage, bone, and adipose tissue

tissue

aggregate of differentiated cells with similar properties

tissue categories

muscle tissue, nervous tissue, epithelial tissue (epithelium) connective tissue

what do connective tissues form

extracellular matrix for cell attachment and signaling in all tissues.

organ

a collection of tissues joined in a structural unit to serve a common function

organ system

organs that are linked together to serve an overall function (the cardiovascular system)

organ funcition

coordinates the activities of these systems to maintain a stable internal environment

what makes up the internal environment

liquids, often have similar make up as salt water

extracellular fluid (ECF)

internal sea that is enclosed, outside of cells

• 1/3 of body fluid

  • made of plasma interstitial fluid (ISF)

Interstitial fluid

fluid between cells part of ECF

intracellular fluid (ICF)

fluid inside of cells

• ⅔ of water

in animals with closed vascular systems

extracellular fluids are compartmentalized to enable exchange of nutrients and waste

Percentage of body that is water

60%

kg to L

1kg = 1L

what percent of ECF is inside cardiovascular system as plasma

20

what perectn of ECF in interstitial fluid

80

Where else can blood volume be found?

white blood cells, blood cells, and RBCs

What separates the intracellular fluid from the extracellular fluid

cell membrane or plasma membrane, ECF is like seawater

What separates the interstitial fluid from blood plasma

capillary wall, maintains the compositions of the plasma

plasma vs interstitial fluid

plasma has plasma proteins ISF doesnt

plasma proteins functions

keep fluid inside the cardiovascular systems

what is it called when there is too much interstitial fluid

edema

homeostasis

our body does everything to maintain balance

Claude Bernard

french physiologist who talked about a well regulating internal environment

Dr walter Cannon

coined the term homeostasis

whenever there is a change in extracellular fluid composition

body initiates reactions to correct or to minimize that change

Examples of homeostatic control systems

ions fluids blood sugar body temp

Reflex arc

the pathway mediating a reflex

stimulus

a detectable change in the controlled variable

receptor

sensor that a stimulus acts on

integrating center

signal is then relayed from the receptor to here

afferent pathways

neural or hormonal (towards CNS)

where does the integrating center send the input to

effector via efferent pathways (go away from CNS)

in homeostatic control the response

decreases effect of the stimulus

feedforward mechanism

helps negative feedback sometimes, they ANTICIPATE changes to adapt before a stimulus

examples of feedforward process

cues to activate digestive system

preperation for excersize to reduce lag and buffer adrenaline rush

positive feedback

magnifies a change → explosive reaction

examples of positive feedback

control for contractions during childbirth or blood clotting

intracellular chemical messangers

help with communication between cells to cause a response

different types of messangers to help with communication

hormone, neurotransmitter, paracrine and autocrine agents

hormone

chemical messanger secreted by endocrine cells into the blood stream

neurotransmitter

chemical messanger released by a neuron to aggect a muscle gland or nerve cell through the synaptic cleft

paracrine agent

chemical messanger released by a cell that acts on nearby cells

autocrine agent

a chemical messanger released into the interstital fluid that acts upon the very cell that secreted it.

what charachteristic determines name of messanger

where it travels, the same substance can be a neurotransmitter in once place and a hormone somewhere else

negative balance

results in a loss of substamce in the body

positive balance

results in a gain of substance in the body

adaptation

inherited biological control mechanism

acclimation

changes bc of prolonged exposure to a stimulus or stress