Chapter `1 - The Study of Body Function

physiology

the study of biological function; how the body works

1) concerned with the norma function of cells to the organism as a whole

2) emphasizes mechanisms - how it works

3) explains using cause and effect sequences

4) derived from scientific experiments

4 parts of physiology as a science

pathophysiology

concerns how disease or injury affects physiological processes which can aid in understanding normal processes

comparative physiology

studies the differences and similarities in the functions of invertebrates and vertebrates

pharmaceutical drugs

what has comparative physiology aided in the development of

1) make observations

2) form a testable hypothesis

3) design and conduct experiments (or make observations)

4) analyze the data

5) replicate multiple times in order to accept conclusion

6) hypothesis may become a general theory

6 steps of the scientific method

1) quantifiable measurements

2) an experimental group and a control group

3) reduction of bias

4) statistical analysis

5) review and publication by a peer-reviewed journal

what 5 things does good physiological research require

a variable that we don’t account for but impacts the results

what is a confounding variable

variable that we account for and may impact the results, but it can’t be manipulated (age, gender, ethnicity, etc)

what is an extraneous variable

begins by studying the effects of a chemical on cells in vitro (in a culture dish)

how does research on developing pharmaceuticals begin

studying on animals (mice and rats) to see if the same effects occur in vivo (in a living creature) and if there are any toxic side effects

after studying chemicals in vitro, what is the next step in developing pharmaceuticals

they are genetically modified (transgenic) to be susceptible to particular disease

for the animal trials used when developing pharmaceuticals, what is done to the animals

test the drug on healthy human volunteers to test for side effects, rates of passage, dosage, etc

phase 1 of clinical trials for pharmaceutical drugs

test the drugs effectiveness on people with the particular disease (ONLY has that disease and no other health issues)

phase 2 of clinical trials for pharmaceutical drugs

trials are conducted on a large number of people to include both sexes, many age groups and ethnicities, and people with more than 1 health condition (this is where FDA can approve the drug)

phase 3 of clinical trials for pharmaceutical drugs

trials test other applications for the drugs (can it be used for something else)

phase 4 of clinical trials for pharmaceutical drugs

Erasistratus

first physiologist

Aristotle

physiologist that speculated about body function (thinkers, not doers)

William Harvey

physiologist that demonstrated that the heart pumps through a closed system of vessels

Claude Bernard

physiologist that observed that the internal environment stays relatively constant although changes are occurring

Walter Cannon

physiologist that coined the term homeostasis to describe the internal consistency of the body

homeostasis

constancy of the internal environment in a everchanging external environment

to maintain homeostasis

what is the main purpose of our physiological mechanisms

disease

what does a persistent, prolonged deviation form homeostasis indicate

negative feedback loops

which type of feedback loop is homeostasis most often accomplished by

different blood types

what did Landsteiner discover

antibodies - humoral immunity

what did Von Behring discover

digestion

what id Pavlov discover

autonomic nervous system

what did Langley discover

structure of DNA

what did Crick, Watson, Franklin, and Wilkins discover

1) stimulus

2) receptors

3) integrating center

4) effector

4 parts of a negative feedback loop pathway

act as sensors in the body to detect change and send information to the integrating center

what do receptors do in the negative feedback loop pathway

assesses change around a set point and sends instructions to an effector

what does the integrating center do in the negative feedback loop pathway

muscles or glands that can make the appropriate adjustments to counter the change from the set-point

what does the effector do in the negative feedback loop pathway

average of a range of agreeable conditions

what is a set point

moves in opposite direction from the change, makes change from set-point smaller, reverses change in the set-point, and is a continuous process

mechanism of negative feedback loops

antagonistic effectors - they move in opposite directions as the change that occurred

what type of effectors are involved in negative feedback loops

dynamic constancy

maintaining conditions within a certain normal range is referred to as

allows us to have knowledge of normal ranges which aids in diagnosing diseases and assessing the effects of drugs and treatments in experiments

what is the importance of quantitative measurements in physiology

7.35 to 7.45

what is the normal range for arterial pH

4.5 to 5.5 mEq/L

what is the normal range for calcium

70 to 99 mg/100 mL

what is the normal range for blood glucose

the end product in a process stimulates the process and the action amplifies the changes that stimulated the effectors

what is positive feedback

negative feedback loops at the end to end the process

what does positive feedback ultimately end up involving

intrinsically or extrinsically

2 ways in which regulation of processes within organs can occur

intrinsically regulating

cells within the organ sense a change and signal to neighboring cells to respond appropriately

extrinsically regulating

the brain (or other organs) regulates an organ using the endocrine or nervous system

it releases hormones into the blood which travel the circulatory system and are transported to the target organ (slow process)

how does the endocrine system regulate processes within organs

it “innervates” organs with never fibers (directly targets organ so quicker)

how does the nervous system regulate processes within organs

specific stimuli

what are hormones secreted in response to

cell

basic unit of structure and function of living things

tissue

group of similar cells that perform a similar function

organ

group of 2 or more tissues into structural and functional units

system

group of organs that work together to perform related functions

organism

systems working together in coordination

muscle, nervous, epithelial, and connective tissue

4 major categories of tissues that our organs are composed of

skeletal muscle, cardiac muscle, and smooth muscle

3 types of muscle tissues

voluntary (can consciously control it)

what type of muscle is skeletal muscle tissue

bone that are pulled to produce movements

what is skeletal muscle tissue most associated with

tongue, esophagus, sphincters, and diaphragm

which skeletal muscle tissues do not cause skeletal movement

a graded response

what type of response can skeletal muscles produce

only in the heart

where is cardiac muscle tissue found

they are short, branched, and interconnected both physically and electrically

what are the fibers of cardiac muscle tissue like

involuntary (can’t consciously control it)

what type of muscle is cardiac muscle tissue

sodium ion to flow between cardiac muscle cells

what do intercalated discs allow for

in the walls of digestive, urinary, and reproductive organs, blood vessels, and bronchioles of the lungs (hollow organs)

where is smooth muscle tissue found

not striated and involuntary

is smooth muscle tissue striated? and what type of muscle is it?

peristalsis

coordinated, wave-like contraction of smooth muscle layers to more substances through the organs

in the brain, spinal cord ad nerves

where is nervous tissue found

neurons → functional units of the NS, responsible for conducting impulses

neuroglia → support neurons by providing structural and metabolic assistance

what are the 2 main types of cells that nervous tissue is composed of and what are their main functions

dendrites → receive signals

axons → transmit signals

cell body → contains the nucleus and serves as the metabolic center

3 key parts of the neuron and what it does

the membranes that cover body surfaces, line hollow organs, and make up glands

what does epithelial tissue form

based on number of cell layers and based on the shape of their cells

how are epithelial membranes classified

simple epithelium → one layer and is specialized for transport of substances (ex. lining of blood vessels)

stratified epithelium → composed of multiple layers and provides protection

(ex. skin)

2 classifications based on layers for epithelial tissue

squamous → flattened cells

cuboidal → as tall as they are long

columnar → tall cells

3 types of classifications based on cell shape for epithelial tissue

goblet cells → secrete mucous

cilia → move in a coordinated fashion

what do goblet cells and cilia do

allows for rapid diffusion as in the alveoli of the lungs

function of simple squamous epithelium

allows for secretion of substances as in various glands

function of simple cuboidal epithelium

allows for absorption as found in the wall of the small intestine

function of simple columnar epithelium

intercellular junctions (junctional complexes) and nourished by underlying connective tissues (since too close together for blood vessels)

what are cells of stratified epithelial tissues held together by and what are they nourished by

anchored by a basement membrane

how is epithelial tissue attached to connective tissue

the membranes have living cells in all layers → found in the mouth, esophagus, and vagina to protect against abrasion while maintaining moisture

what are nonkeratinized stratified epithelial tissue and where are they found

the membranes have cells filled with keratin (water-resistant protein) and layers of dead cells on the surface → found in the skin

what are keratinized stratified epithelial tissue and where are they found

renew by losing surface cells and replacing them with new cells

what do keratinized stratified epithelial tissue constantly do

epithelial tissue

what tissue are exocrine glands derived from

secrete substances through ducts to specific locations in the body

what do exocrine glands do

lacrimal (produce tears), sweat, sebaceous, digestive enzyme, and the prostate

examples of exocrine glands

as tubes or as acini

how may the secretory portion of exocrine glands be structured

eccrine (or merocrine) → found all over (more numerous) and secrete a salty sweat involved in thermoregulation

apocrine → in the axilla and pubic regions and releases a protein-rich seat that bacteria feed on (causing body odor)

two main types of sweat glands and where they are

epithelial tissue

what tissue are endocrine glands derived from

they lack ducts, so they release their products (hormones) directly into the bloodstream via capillaries

how do endocrine glands differ from exocrine glands

exocrine glands forms if epithelial cord if present

endocrine glands form if surface epithelial cells grow down into the underlying tissue

when do endocrine vs exocrine glands form from epithelial tissue

connective tissue proper, cartilage, bone, and blood

4 major categories of connective tissue

protein fibers, extracellular material, and specialized cells

what is the connective tissue matrix mad up of

protein fibers, like collagen, and a gel-like ground substance that provides support the flexibility

what is connective tissue proper made up of

1) loose has scattered collagen fibers allowing space for nerve vessels and nerves to pass through (dermis of skin)

2) dense regular has tightly packed collagen fibers with minimal ground substance making it strong and resistant to stretching (tendons and ligaments)

loose vs dense regular connective tissue proper

stores fat (cells called adipocytes) to store energy, provide insulation, and cushion cells

what is adipose tissue

composed of densely packed collage fibers arranged in various directions providing strength and flexibility (dermis of skin and capsules surrounding organs)

what is dense irregular connective tissue composed of and used for

cells called chondrocytes surrounded by a semi-solid ground substance allowing it be flexible, but supportive

what is cartilage connective tissue composed of and used for

it serves as a template skeleton

during bone development, what is the purpose of cartilage