Physiology Lecture 1

Levels of biological organization

-chemical level

-cellular level

-tissue level

-organ level

-organ system level

-organism level

Chemical level: The four major classes of biomolecules

-protein

-lipid

-carbohydrate

-nucleic acids

Biomolecules are what

the building blocks of life (cells, tissues, organs) and how tissues get their function

Protein building block and function

-building block is amino acid

-function: fundamental component of structure and dynamic metabolic function in the cell

Lipid building block and function

-building block-no single building block for all lipids

-function- Long term energy molecule, structural component of the membrane bilayer (phospholipid), and integral extracellular membrane facilitator of cell-cell interactions (glycolipid)

Carbohydrate building block and function

-building block-monosaccharide

-function-structural molecule, attachment on protein for cell recognition and short and long term energy storage (glycogen)

Nucleic acids building block and function

-Building block-nucleotide

-function-unit for hereditary info and protein biosynthesis

-DNA and RNA

What are the living unit of life

cells

All cells comprise at least

1. Membrane

2. Genetic material

3. Cytosolic fluid

Cell membrane

-lipid bilayer surrounding cell or organelle

-interacts with other molecules and dictates how it will react

Genetic material

DNA

Cytosolic fluid

-Fluid component of the cell interior

-Brings nutrients, electrolytes to rest of body/cell

The four major categories of tissues

-Connective

-Muscle

-Epithelial

-Nervous

Connective tissue

-Provides support/ integrity for other tissues/organs

-Has varied cell arrangement and order

Muscle tissue

-Generates mechanical force

-Includes skeletal, smooth, and cardiac

-Skeletal (voluntary)

-Smooth (involuntary)

-Cardiac (involuntary)

Epithelial tissue

-Lines walls of open tubes

-Provides secretory and absorptive surfaces

-Basal

-Apical

-The way the cells are aligned give function

Nervous tissue

-Gila provide protection, nourishment and support to nerve cells

-Nerves provide long-distance communication within the body

CT cells

connect, anchor and support structures of the body

Types of CT include

-loose connective

-dense connective

-blood

-bone

-cartilage

-adipose

Epithetlial cells are

specialized for the selective secretion and absorption of ions and organic molecules and for protection

Epithelial cells are characterized and named according to

their shape

These shapes include

-cuboidal (cube-shaped)

-columnar (elongated)

-squamous (flattened)

-cilated

Epithelial tissue (epithelium) may form

from any type of epithelial cell

Shape gives rise to the

function

Epithelial layering

-simple epithelium

-stratified epithelium

Simple epithelium

epithelia arranged in single cell thick tissue

Stratified epithelium

A thicker tissue consisting of numerous layers of cells

The epithelia cells rest on what layer

An extracellular protein layer called the basement membrane and has two sides (basolateral and apical)

Basolateral side

The side of the cell anchored to the basement membrane

Apical side

-The opposite side, which typically faces the lumen or exterior surface

-Goes toward opening

The two sides of all the epithelial cells in the tissue may perform

different physiological functions

The epithelial cells are held together by

-They are held together along their lateral surfaces by extracellular barriers called tight junctions

Tight junctions

-Enable epithelia to form boundaries between body compartments and to function as selective barriers regulating the exchange of molecules

Five functional categories of epithelia

-Exchange

-Transporting

-Cilated

-Protective

-Secretory

Exchange

-Number of cell layers

-Cell shape

-Special features

-Where found

-Number of cell layers: One

-Cell shape: flattened

-Special features: Pores between cells permit easy passage of molecules

-Where found: Lungs, lining of blood vessels

Transporting

-Number of cell layers

-Cell shape

-Special features

-Where found

-Number of cell layers: One

-Cell shape: Columnar or cuboidal

-Special features: Tight junctions prevent movement between cells; surface area is increased by folding of cell membrane into fingerlike microvilli

-Where found: Intestine, kidney, some exocrine glands

Cilated

-Number of cell layers:

-Cell shape:

-Special features:

-Where found:

-Number of cell layers: One

-Cell shape: Columnar or cuboidal

-Special features: One sie covered with cilia to move fluid across surface

-Where found: Nose, trachea, and upper airways, female reproductive tract

Protective

-Number of cell layers:

-Cell shape:

-Special features:

-Where found:

-Number of cell layers: many

-Cell shape: flattened in surface layers: polygonal in deeper layers

-Special features: cells tightly connected by many desmosomes

-Where found: Skin and lining of cavities (like mouth), that open to the enviroment

Secretory:

-Number of cell layers:

-Cell shape:

-Special features:

-Where found:

-Number of cell layers: One to many

-Cell shape: Columnar or polygonal

-Special features: Protein-secreting cells filled with membrane-bound secretory ganules and extensive RER.

Steroid-secreting cells contain lipid droplets and extensive SER

-Where found: Exocrine glands including pancreas, sweat glands, salivary glands; endocrine glands (thyroid and gonads)

Muscle types

cardiac: involuntary

smooth: involuntary skeletal: voluntary

Nervous tissue cell

neuron

Neuron

A cell of the nervous system that is specialized to initiate, integrate and conduct electrical signals to other cells

What forms nervous tissue

A collection of neurons

Examples of nervous tissue

brain and spinal cord

What forms a nerve

Axons from many neurons are packaged together along with CT

Organ systems

-integumentary

-endocrine

-reproductive

-nervous

-immune/lymphatic

-cardiovascular

-respiratory

-urinary

-musculoskeletal

-digestive

Integumentary system; organs and tisses

skin

hair

nails

sweat

oil glands

Integumentary system; functions

protection

defense

body temp

Endocrine system; organs and tissues

Hormone-secreting glands (ex:thyroid)

Endocrine system; functions

coordination of body functions

Reproductive system; organs and tissues

-Female: ovaries, fallopian tubes, uterus, vagina, mammary tissue

-male: testes, penis, vas defenes, glands

Reproductive system; functions

Production of reproductive components and support for developing fetus

Nervous system; organs and tissues

brain, spinal cord, nerves

Nervous system; functions

Detection and coordination of response

Immune/lymphatic; organs and tissues

lymphoid tissues, spleen, various types of cells, thymus,

Immune/lymphatic; functions

Defense againest pathogens, fluid balance

Cardiovascular system; organs and tissues

heart, blood vessels, blood

Cardiovascular system; functions

movement of blood throughout the body

Respiratory system; organs and tissues

nasal passages, trachea, lungs

Respiratory system; functions

Oxygen and carbon dioxide regulation

Urinary system; organs and tissues

kidneys, ureters, bladder, urethra

Urinary system; functions

filtration of blood and removal of waste

Musculoskeletal system; organs and tissues

bone, skeletal muscle, cartilage, tendons, ligaments

Musculoskeletal system; functions

Movement, support/protection, blood formation

Digestive system; organs and tissues

mouth, salivary glands, esophagus, stomach, liver, gallbladder, pancreas, small intestine, large intestine

Digestive system; functions

breakdown of food, nutrient absorption

Organs are composed of

multiple tissue types

ex: blood vessels have layers of smooth muscle cells, endothelial cells and fibroblasts

Organ systems contain

multiple organs that work together

ex: the urinary system has the kidney, ureters, urehtra, bladder

Most of our body's fluid is in which physiological compartment?

intracellular

Mitochondrial structure

Specialized folds of mitochrondrial membrane

Mitochondrial function

Increase surface area for proteins that carry out mitochrondrial respiration

More surface area=

more energy

Characteristics of life

-Eat (energy production/consumption)

-change (growth/repair)

-survive (reproduction)

-respond (adaptation)

Eat

•Brings nutrients into body

•Humans' primary energy source is ATP

•Humans are heterotrophs

Change

•Cells, tissue and organs grow and change over time

•Tissues repair themselves after injury

Adaptation

•Transient and/or permanent changes based on environment

Reproduction

•Required for survival of the species, not the individual (humans)

Maintenance of what is necessary for like

fluid compartment volumes

ICF

Fluid inside cells

ECF

Fluid outside/around the cells

Fluid imbalance can lead to

-dehydration of cells

-imbalance in ion concentrations

-cell death (if prolonged)

Fluid movement

-Occurs by osmosis

-Is impacted by ion concentrations

The immediate environment that surrounds each individual cell in the body is the

extracellular fluid which consists of a mixture of proteins, polysaccharides, and maybe minerals

ECF (extracellular fluid) general functions

•It provides a scaffold for cellular attachments, and

•It transmits information, in the form of chemical messengers, to the cells to help regulate their activity, migration, growth, and differentiation.

Extracellular fluid volume equation

ECF Volume= sum of the plasma + interstitial volumes

Blood (plasma) makes up

20-25%

Interstitial fluid makes up

75-80%

The space containing interstitial fluid is called the

interstitim

Mechanisms of fluid movement: hydrostatic pressure

Pressure exerted on the wall of a vessel due to fluid volume

Mechanisms of fluid movement: hydrostatic pressure, capillary filtration arterial end

-increase in hydrostatic pressure

-decrease in colloid osmotic pressure

-plasma and nutrient out

Mechanisms of fluid movement: colloid osmotic pressure

Pressure exerted by proteins on a vessels plasma

Mechanisms of fluid movement: colloid osmotic pressure venous end

-Decrease in hydrostatic pressure

-Increase in colloid osmotic pressure

-Fluid in

Homeostasis

-The process that maintain steady conditions within the human body

-dynamic process

When homeostasis is maintained, we refer to

physiology

When homeostasis is not maintained we refer it to

pathophysiology

Homeostatic set points

established thresholds required for physiological processes to maintain balance

The controller is the

hypothalamus

Negative feedback

Returns the body back to the homeostatic set point or set range

Positive feedback

The physiological response elicited by the stimulus acts to increase the original stimulus

Stimulus parts

Sensor

Control

Effector