Under the microscope CORE273 Summer2019 What is Biology? Biology is a word derived from the Greek words bios, meaning “life”, and logos meaning “study”. Therefore biology is defined as the science and study of life and living organisms. An “organism” is a living entity consisting of one cell (bacteria) or several cells (plants, animals, fungi). https://www.ntnu.edu/biology/about-us/what-is-biology 2 Characteristics of Living things Made of different molecules than non-living things. Carbon atoms form bonds with other atomic elements. Molecules result: carbohydrates, proteins, lipids, nucleic acids. Require energy and raw materials. Intake of above molecules offers energy and building blocks of cells. Have a metabolism. Breaks down/builds up molecules into/from atoms (respectively). Living things will grow, reproduce, and evolve. Characteristics of Living things Respond to their environment and maintain homeostasis. Necessary to maintain a relatively constant internal environment. Systems present in any organism must respond to internal/external stimuli. Make adjustments to compensate for stress on other systems. Negative Feedback Loops Controlled Variable is the factor being monitored. Sensors keep “tabs” on if these factors are at their “set points”. Control Center gathers information and determines appropriate actions. Effectors are activated by control center to carry out necessary response. Characteristics of Living things All living things are composed of cells and cell products. A single cell is the smallest unit exhibiting all characteristics of life. Often divided by internal structural organization: Prokaryotic cells lack a membrane bound “nucleus” and have few “organelles” (i.e.; bacteria) Eukaryotic cells do have a membrane bound nucleus and many organelles with different functions (i.e.; plants, animals, fungi) Inside our human Cells Nucleus is the “brain”; directs activities via DNA. DNA molecules contain our genetic information. Organelles are “little organs” Ribosomes: produce proteins. Rough endoplasmic reticulum: produces proteins via ribosomes that are on membrane. Smooth endoplasmic reticulum: produces primarily lipids; no ribosomes. Golgi apparatus: refines, ships, and packages products from both endoplasmic reticula. Mitochondria: “powerhouse”. Produces energy in the form of ATP molecules. Cells of the body While the internal structure remains fairly similar between cells of the body, cells can differ in external structure. The form (shape/size) of a cell will greatly influence it’s overall function. Neurons are long and thin for fast communication between cells. Muscle cells have special segments that shorten to allow the tissue to contract. Tissues of the body Groups of similar cells come together to form tissues. There are four primary types of tissues: Epithelial: covers body cavities, lines organs, and surfaces. Glandular epithelium secretes products. Connective: supports and connects. Loose, d ...

1. Under the microscope
CORE273 Summer2019
What is Biology?
Biology is a word derived from the Greek words bios, meaning
“life”, and logos meaning “study”.
Therefore biology is defined as the science and study of life and
living organisms.
An “organism” is a living entity consisting of one cell (bacteria)
or several cells (plants, animals, fungi).
https://www.ntnu.edu/biology/about-us/what-is-biology
2
Characteristics of Living things
Made of different molecules than non-living things.
Carbon atoms form bonds with other atomic elements.
Molecules result: carbohydrates, proteins, lipids, nucleic acids.
Require energy and raw materials.
Intake of above molecules offers energy and building blocks of
cells.
Have a metabolism.
Breaks down/builds up molecules into/from atoms
(respectively).
Living things will grow, reproduce, and evolve.
Characteristics of Living things
Respond to their environment and maintain homeostasis.

2. Necessary to maintain a relatively constant internal
environment.
Systems present in any organism must respond to
internal/external stimuli.
Make adjustments to compensate for stress on other systems.
Negative Feedback Loops
Controlled Variable is the factor being monitored.
Sensors keep “tabs” on if these factors are at their “set points”.
Control Center gathers information and determines appropriate
actions.
Effectors are activated by control center to carry out necessary
response.
Characteristics of Living things
All living things are composed of cells and cell products.
A single cell is the smallest unit exhibiting all characteristics of
life.
Often divided by internal structural organization:
Prokaryotic cells lack a membrane bound “nucleus” and have
few “organelles” (i.e.; bacteria)
Eukaryotic cells do have a membrane bound nucleus and many
organelles with different functions (i.e.; plants, animals, fungi)
Inside our human Cells
Nucleus is the “brain”; directs activities via DNA.
DNA molecules contain our genetic information.
Organelles are “little organs”
Ribosomes: produce proteins.
Rough endoplasmic reticulum: produces proteins via ribosomes
that are on membrane.

3. Smooth endoplasmic reticulum: produces primarily lipids; no
ribosomes.
Golgi apparatus: refines, ships, and packages products from
both endoplasmic reticula.
Mitochondria: “powerhouse”. Produces energy in the form of
ATP molecules.
Cells of the body
While the internal structure remains fairly similar between cells
of the body, cells can differ in external structure.
The form (shape/size) of a cell will greatly influence it’s overall
function.
Neurons are long and thin for fast communication between cells.
Muscle cells have special segments that shorten to allow the
tissue to contract.
Tissues of the body
Groups of similar cells come together to form tissues.
There are four primary types of tissues:
Epithelial: covers body cavities, lines organs, and surfaces.
Glandular epithelium secretes products.
Connective: supports and connects.
Loose, dense, cartilage, adipose, bone, and blood.
Muscular: contracts for forms of movement.
Skeletal, cardiac, and smooth.
Nervous: generates and transmits impulses for
“communication”.

4. Organs and Organ systems
Tissues come together to form organs which are self-contained
combinations of tissues with specific vital functions.
Organ systems are combinations of multiple organs working
together for larger functions of life.
Chapter summary slide #1
Biology is the study of life and living organisms
Organisms are “living” if they are made of different molecules
(carbohydrates, proteins, lipids, and nucleic acids), require
energy and raw materials, have a metabolism, grow, reproduce,
evolve, respond to their environments and maintain
homeostasis.
Homeostasis is a relatively constant/balanced internal
environment.
Homeostasis is controlled by negative feedback loops consisting
of controlled variables, sensors, control center, and effectors
(know functions of parts).
All living things are composed of cells and cell products.
Cells can be eukaryotic (nucleus/organelles) or prokaryotic (no
nucleus/organelles).
Chapter summary slide #2
Human cells are eukaryotic and have a membrane bound nucleus
(DNA) and organelles such as ribosomes (protein), rough
(protein) and smooth (lipids) endoplasmic reticuli, golgi (refine,
package, and ship) and mitochondria (ATP energy).
Cells can come in all shapes and sizes; form influences
function!
Cells of similar functions come together to form tissues; four
main types are epithelial (covers body cavities, lines organs and

5. surfaces), connective (supports and connects), muscular
(contracts for movement), and nervous (impulses for
communication).
Tissues come together to form organs (stomach, brain, heart,
etc.).
Organs come together into organ systems (digestive, endocrine,
urinary, etc.).
Holding it Together
CORE273 SUMMER2019
Integumentary system
Primarily hair, skin, and nails.
Epidermis is the top, visible layer of skin.
Dermis is below the epidermis.
Nerves, blood vessels, glands, smooth muscle.
Hypodermis: fat and other connective tissue.
Subcutaneous meaning “under the skin”.
Not a primary layer of skin, but offers insulation, protection,
and energy storage.
Epidermis
Stratified squamous epithelium
“Layers” of “squashed” epithelial cells.
Cells continuously made and replaced.
Basal keratinocytes at bottom of epidermis reproduce.
They move upward and become keratinocytes producing hard,
waterproof keratin protein.
The farther they get from the bottom, they dry out and die
leaving a hard, waterproof barrier; line of defense!!
Gives skin its color and protection from the sun.
Melanocytes produce UV blocking melanin pigment.

6. dermis
Regulates and detects temperature.
Sweat glands, thermoreceptors, erector pili muscle.
Gives skin its shape and pliability.
Collagen (strong) and elastin (stretchy) fibers.
Dermal papillae for fingerprints.
Has ample blood supply for all cells in the tissue.
Nerves and receptors take in sensory stimuli.
Aids in protection and immunity.
Oil (sebum) limits growth of bacteria/fungi.
Blood supply brings in other immune cells.
Skeletal system
Approximately 206 bones in the body.
Bone is a specialized connective tissue made of collagen fibers,
calcium, and phosphate.
This system functions to:
Give the body support and shape.
Aid in body movements.
Store minerals (99% of calcium).
Store fat as yellow bone marrow.
Produce new blood cells.
Red bone marrow deep inside bones.
Bone formation
Chondroblasts build a hyaline cartilage mold during
development.
Osteoblasts build bone by laying down mineral matrix and

7. releasing enzymes to harden it into bone (called ossification).
Osteoblasts get “stuck” in the bone and mature into osteocytes
which work to maintain bone.
Structure of bone
Compact bone is dense and strong.
Formed by cylindrical units called osteons.
Osteocytes are “stuck” throughout as mentioned.
Central canal holds blood vessels and nerves.
Canaliculi “little canals” between central canal and cells.
Provides nutrition and communication to and between cells
Spongy bone also forms.
Porous and web-like pattern known as trabeculae.
Offers storage space and strength without extra weight.
Periosteum connective tissue wraps around bone.
Bone Growth
Bone grows in length as it continues to ossify.
Lengthening occurs at epiphyseal “growth” plate until ages 18-
21.
Chondroblasts build new cartilage on the outer edge.
Osteoblasts build bone on the inner edge.
Mediated by hormones (esp. growth hormone).
When hormones subside, chondroblasts stop and osteoblasts
turn the remaining cartilage to bone.
Plate now called the epiphyseal line; no more lengthening
occurs!
Bone growth

8. Osteoblasts and osteoclasts work together to maintain and
restore bone throughout life.
Their opposing roles help maintain homeostasis!!
Once bones stop growing longer, they can still have:
Changes in mass through mineral deposition and storage.
Changes in shape as response to weight-bearing shifts.
Posture, exercise, bone damage, etc.
Bones of the body
Bones range in size and shape.
They come together to form our skeleton.
Axial skeleton follows the midline of our body.
Skull (including cranial and facial bones), vertebral column,
ribcage, and breast bone.
Appendicular encompasses all other bones.
Pectoral girdle and upper limbs.
Pelvic girdle and lower limbs.
Joints/articulations
Where bone meets bone in the skeleton, a joint forms.
Ligaments are dense connective tissue that hold bones together.
Joints are classified by mobility:
Fibrous (immobile) ex: suture joints in skull.
Cartilaginous (slightly mobile) ex: joints connecting ribs to
sternum.
Synovial (mobile) ex: knees, shoulders, etc.
Held together with a joint capsule composed of a synovial
membrane, fluid, and cartilage to cushion the joint and reduce
friction.
Muscles and tendons offer stability and potential for movement.

9. Chapter summary slide #1
Integumentary system is hair, skin, and nails.
Skin has two layers; dermis (many cell types) and epidermis
(stratified squamous cells).
In epidermis, basal keratinocytes reproduce and push new cells
upwards.
Keratinocytes make keratin to make cells hard and waterproof.
As they die, keratin stays behind as protective barrier on skin.
In epidermis melanocytes give melanin pigment for UV
protection/skin color.
Dermis controls temperature (glands, receptors, muscle), gives
skin its shape and pliability (collagen/elastin), blood supply,
nerves and receptors, protection and immunity (sebum and
blood).
Chapter summary slide #2
There are 206 bones in the human body made of collagen,
calcium, and phosphate.
Support/shape, body movement, mineral storage, fat (yellow
marrow), make blood cells (red marrow).
“mold”.
balance.
Osteocytes – cells”.
Osteocytes are stuck in osteons in compact bone; unit of bone
that is dense and very strong.
Spongy bone offers more storage and strength to bone without
extra weight.
Bone grows in length until 18-21, then changes in mass
(minerals) or shape (weight-bearing).

10. Chapter summary slide #3
Skeleton can be divided into axial and appendicular portions.
Axial is skull (cranial and facial bones), vertebral column, ribs,
and sternum.
Appendicular is everything else; pectoral girdle and upper limb
bones, pelvic girdle and lower limbs.
Joints/articulations form where bones come together in
skeleton.
Ligaments hold bone to bone at joints.
Joints can be fibrous (immobile), cartilaginous (slightly
mobile), and synovial (very mobile).
Synovial joints move better because of synovial membrane,
fluid, and cartilage to cushion and lubricate the joint from
friction.
On the move
Core273 summer2019
Skeletal Muscular system
Attaches to the skeleton and carries all the body’s movements.
Skeletal muscle is voluntary meaning it requires conscious
activation.
Muscle attached to bones via tendons.
Origin tendon is where the muscle is “anchored”.
Attachment is “pulled” on to produce movement.
Muscles seldom work 100% individually.
Some muscles are synergistic and help others perform a
movement.
Some are antagonistic to balance one action by performing the
opposite.

11. Skeletal muscle organization
Sarcomeres are the smallest contractile unit of muscle.
Sarcomeres are an organization of myofibrils.
Actin and myosin filaments.
Myofibrils are bundled to form muscle cells (fibers).
Muscle cells are bundled into fascicles covered in connective
tissue fascia.
Fascicles are bundled into the “whole” muscles.
Muscle contraction
Nerve impulse stimulates the muscle cell.
Stimulation releases calcium.
Calcium activates myofibril filaments.
Sliding Filament Mechanism ensues.
Sarcomere shortens and muscle contracts.
When impulse ends, muscle/sarcomere relaxes and goes back to
its resting length.
Sliding filament mechanism
Characteristics of contractions
Strength: number of motor units activated.
Unit is the motor neuron and the muscle cells that it controls.
Pace: how quickly a muscle “twitch” occurs.
Twitch: entire cycle of contraction.
Fast twitch; muscle fibers/cells that contract quickly, using

12. energy quickly, and ultimately fatiguing quickly.
Slow twitch; contract slowly, use energy slowly, fatigue slowly.
Characteristics of contractions
Dynamics; muscle length and tension.
Isotonic; muscle length changes but tension does not.
Produces movement!
Concentric: muscle length shortens.
Eccentric: muscle elongates.
Isometric; muscle length does not change, but tension does.
Static tension or “isostatic” meaning no movement!
Other muscle types
Cardiac muscle is found only in the heart.
Involuntary: no conscious effort for contraction.
Relaxes as much as it contracts.
Generates its own electrical impulse!
Smooth muscle is found in many internal organs.
Involuntary as well.
Contracts for long periods of time.
Does not “shorten and lengthen”.
Filaments arranged in at angles in bundles, not linear
sarcomeres.
Nervous system
Processes sensory input and produces an action output.
Composed of a cell system of neurons
Cell body: contains nucleus and organelles.
Dendrites: where neural messages are received in neuron.

13. Axons: portion of neuron that sends neural messages.
Axons meet dendrites at synapses for communication.
Central Nervous System: brain and spinal cord.
Peripheral Nervous System: all other nerves; receptors and
effectors.
Depolarization and myelin
Depolarization describes the “sending of a message (impulse)”
down a neuron.
Neurons have negative (-) resting charges.
Stimuli at dendrites cause sequential shifts to positive (+)
charges through cell body and then down entire axon (all
surface area!).
Myelin sheath speeds up depolarization.
Fatty deposits of insulation cover portions of axon.
Decreases amount of surface area.
Depolarization “jumps” over these portions to speed up
impulses.
Neural Synapses
When depolarization reaches the end of the presynaptic axon
(axon terminal), the message must cross a space (synapse) to the
dendrites of the postsynaptic cell.
Since depolarization can’t “jump” through thin air,
neurotransmitters are used instead.
Neurotransmitters are chemical messengers.
Released from terminal, diffuse across space, bind to receptors
on dendrites of next cell.
Subsequent depolarization in next cell if excitatory or not if
they are inhibitory.

14. Sensory Pathway
Sensory receptors throughout the body pick up on stimuli.
Taste, touch, smell, sight, sound, body position, pain, temp.,
etc.
Receptors depolarize sensory neurons sending information to
CNS.
Sensory neurons at similar body levels gather into nerves to
enter the spinal cord through spinal nerves.
Ascending interneurons carry the sensory information to the
brain.
Cranial nerves bypass the spinal cord and enter the brain
directly.
Brain regions and function
The brain processes and integrates sensory information which is
directed to the part of the brain responsible for “that” stimuli.
Brain determines an appropriate motor response to the incoming
messages.
Motor pathway
Descending interneurons carry motor response back out to the
body via cranial/spinal nerves.
Nerves branch out into motor neurons which will synapse with

15. various effectors.
Motor pathway effectors can be somatic or autonomic.
Somatic pathways activate skeletal muscle and spinal reflexes.
Autonomic pathways activate involuntary tissues and organs in
either a sympathetic or parasympathetic response.
Somatic Responses
Includes both the conscious and subconscious activation of
skeletal muscles.
Subconscious activation of muscle is a spinal reflex.
Reflexes are protective mechanisms that remove our bodies
from a painful stimulus before the brain even knows what’s
going on!
Interneurons in spinal cord gather pain info from sensory nerves
and immediately activate motor neurons to respond before
sending that same sensory information upward.
Autonomic responses
Sympathetic pathway; “fight or flight”; stress.
Important early in our evolution when we had real-time dangers
to protect ourselves from.
Activates muscles with increased blood pressure, heart rate,
respiratory rate, etc.
Takes blood away from systems that wouldn’t help in the
moment of panic; i.e. digestion.
Parasympathetic pathway; “rest and digest”; calm.
Opposes the sympathetic response to maintain homeostasis
within our bodies!
Chapter summary slide #1

16. Skeletal muscle attaches to the skeleton and produces
movement.
It is voluntary – requires conscious effort.
Tendons attach the muscle to the underlying bones.
Muscles can work together – synergistic.
Muscles can perform opposite actions – antagonistic (important
for balance!)
Actin and Myosin (myofibrils) are organized into sarcomeres.
Chapter summary slide #2
Steps of muscle contraction – this will be a numbering question!
Nerve impulse stimulates the muscle cell.
Stimulation releases calcium.
Calcium activates myofibril filaments.
Sliding filament mechanism ensues.
Sarcomere shortens and muscle contracts.
When impulse ends, return to resting length.
Chapter Summary Slide #3
Contractions can vary by strength (more motor units, more
force), pace (slow or fast twitch fibers), and dynamics (isotonic
for movement or isometric for static tension/no movement).
Specialized muscle types include cardiac (heart) and smooth
(many internal organs).
Both cardiac and smooth are involuntary.
Neurons are the cells of the nervous system.
They have three parts – dendrites (receiving end), cell body,
and axon (sending end).
Central nervous system is the brain and spinal cord.
Peripheral nervous system is everything else; receptors and
effectors.

17. Chapter summary slide #4
Depolarization is the sending of a message via shifts in
membrane charges that must cover the entire surface area of the
neuron to be sent.
The myelin sheath is a fatty insulation that reduces the surface
area along the axon and helps messages (impulses) to be sent
faster via “jumping”.
At synapses, the spaces between axon (terminals) and dendrites,
neurotransmitters cross the gap as chemical messengers to
depolarize the next cell (or turn it off depending on the
message).
Chapter summary slide #5
The brain processes and integrates sensory information;
determines motor response.
ffectors.
Effectors in motor pathway can be somatic or autonomic.
Somatic responses include spinal reflexes that immediately
activate skeletal muscle movements to protect us from painful
stimuli without the brain being consciously aware of them
occurring.
Autonomic responses can be sympathetic (fight or flight; stress)
or parasympathetic (rest and digest; calm) their opposition is
important for homeostasis!
Sensitive types
CORE273 SUMMER2019

18. Sensory MEchanisms
“Senses” interact with one another to make a complex
experience and to allow us to properly respond to both internal
and external cues.
This information is gathered by various receptors throughout
the body.
These may be specialized neurons or separate structures.
Receptors are categorized by the type of stimulus they respond
– or are sensitive – to.
Sense of ToucH
Skin mechanoreceptors respond to pressure or vibration against
the organ.
Receptors trigger a nerve impulse when they are disturbed or
distorted.
Receptors can be free nerve endings or encapsulated structures.
Free nerve endings are activated very easily.
Encapsulated receptors take more stimulus and can adapt over
time.
Sensory neurons carry impulse to the brain to be processed and
integrated.
Sense of touch
Very light touch; sensed by Merkel’s Cells.
Light touch; Meissner’s Corpuscles.
Pressure and stretch; Ruffini Endings.
Vibration and pressure; Pacinian Corpuscles.
Temperature and Pain; free nerve endings in epidermis – cannot
adapt to stimuli!!
Note the differences in capsule size and depth in the skin! This
influences why each receptor type is responsible for a certain

19. type of touch!
Sense of Sight
Photoreceptors in the form of rods and cones in the eye give us
our vision via light energy.
Light enters clear cornea at the front of the eye.
Aqueous humor behind cornea.
Enters through pupil which is controlled by the iris.
Too much light; iris constricts pupil.
Too little light; iris will dilate the pupil.
Moves through the lens.
Can adjust shape to see near vs. far.
Travels through vitreous humor to the retina.
Sense of sight
Retina holds millions of our photoreceptors.
Rods can be activated by low amounts of light but there is no
color and little detail.
Cones offer acute vision and color but need high light for
activation.
Pigments in receptors broken down when light is present, which
activates sensory neurons and send impulses to the brain.
Sense of Hearing
Mechanoreceptors in the ear sensitive to movement.
Sound waves funneled into auditory canal via the pinna.
At end of canal is tympanic membrane (eardrum) which vibrates

20. when the sound waves reach it.
Vibration is carried down a set of three bones called ossicles.
Malleus, Incus, and Stapes.
Sense of hearing
Stapes connects to oval window of the cochlea.
Here, the vibration is amplified; becomes stronger.
Vibrations at oval window cause waves in fluid of cochlea that
move the basilar membrane.
Basilar membrane pushes hair cell receptors along tectorial
membrane.
Hair cells stimulate sensory neurons to produce impulse that
travels to the brain.
Sense of taste
Chemoreceptors sensitive to chemicals on tongue in form of
“taste buds”.
Food chemicals/molecules must be dissolved in saliva to access
receptors.
Taste buds stimulated by chemicals in turn stimulate sensory
neurons.
Message sent to brain about tastes; sweet, salty, sour, bitter,
umami.
Sense of smell
Chemoreceptors in nasal passage.

21. Molecules enter nostrils and dissolve in mucus.
Olfactory receptors are activated by molecules.
They in turn activate sensory neurons.
Signals travel to the brain for processing scent.
Close relationship between taste and smell!
Mouth and nose connected via pharynx.
Smells enhance taste!
Other important senses
Sense of Balance
Semicircular canals in inner ear perceive rotational movement
of the head.
Vestibule deals with gravity, acceleration, and deceleration.
Sense of Body Position
Variety of receptors in body monitor:
How a joint moves.
How muscles contract or relax.
How tendons are stretched.
How skin stretches around joints.
Chapter summary slide #1
Receptors are responsible for gathering sensory information
throughout the body.
They are categorized by the type of stimulus they respond to.
Receptors in turn activate sensory neurons which send info to
the brain.
Mechanoreceptors in skin give us the sense of touch.
Pressure or vibration disturb these receptors.

22. They can be free nerve endings which are activated easily and
cannot adapt (pain and temp).
They may be encapsulated and have potential to adapt.
The depth of the receptor and its capsule size influence the type
of touch it “picks up”.
Chapter summary slide #2
Photoreceptors are activated by light and give us our sight.
Retina holds the photoreceptors; rods and cones.
Rods work in dim light but have no color or acute detail.
Cones need more light but give color and detail.
Mechanoreceptors in ear give us hearing; activated by
vibration/movement.
e
in cochlea.
At oval window vibration causes waves in inner ear fluid which
stimulates mechanoreceptors.
Chapter summary slide #3
Chemoreceptors on tongue in “taste buds” give us taste.
Chemicals need to be dissolved in saliva.
Primary tastes are sweet, salty, sour, bitter, and umami.
Smell is like taste, but receptors are in nasal passage.
Chemicals need to be dissolved in mucus.
Balance and body position are some other important senses in
our body.
Heart of the matter

23. Core273 Summer2019
Respiratory system
The respiratory system brings in oxygen and releases carbon
dioxide waste.
The respiratory tract includes:
Nose
Pharynx
Larynx
Trachea
Bronchi
Bronchioles
Alveoli which make up the lungs.
Inhalation / inspiration
Inhalation or inspiration is the process of “pulling” air into the
respiratory tract.
Nervous system stimulates respiratory muscles in response to
high CO2.
Diaphragm contracts and drops.
Intercostal muscles contract and pull ribs outward.
Increased volume decreases pressure causing vacuum that sucks
in air.
exhalation / Expiration
Exhalation or expiration is the process of “pushing” out used
air.
Opposite mechanism of inhalation.
Signal stops and diaphragm and intercostal muscles relax.
Ribs move inward, diaphragm moves back up.

24. Decreased volume increases pressure and forces air out.
Alveoli in the lungs
Alveoli are thin-walled hollow sacs making up the lungs where
air is collected.
They are wrapped in capillaries; thin walled blood vessels.
The thinness of these walls ensures easy movement of gas and
nutrients through them.
Diffusion of gases
Diffusion is the movement of molecules from areas of high
concentration, to areas of low concentration.
Inhalation = high concentration of O2 in the alveoli.
Gas moves into blood via capillaries where concentration is
lower.
Exhalation = high concentration of CO2 in the blood.
Gas moves into the alveoli where the concentration is lower.
Components of blood
Red blood cells are the cells responsible for transporting the
diffused oxygen.
Hemoglobin is the protein in these cells that oxygen binds to.
White blood cells and antibodies are part of the immune system;
fighting off infection and invaders.
Platelets are cell fragments that are necessary for helping our
blood to clot.
Blood also transports hormones and nutrients to be distributed;
toxins for removal.

25. circulatory system
The circulatory system is responsible for transporting blood,
and all that it contains, through the body.
Blood vessels are pathways blood needs to follow.
Heart is an organ that acts as a pump to push blood through the
vessels and move it in the right direction.
The heart
Heart contains cardiac muscle tissue.
This muscle type is involuntary; no conscious effort.
Electrical impulses for contraction created in the heart.
Pacemaker cells contract quickly and generate electricity.
Send impulse across the atria first to make them contract.
Then through the ventricles so they will contract.
The heart
Atria: top two chambers of the heart; fill with blood then
contract to move it along.
Termed “right atrium” and “left atrium”.
Ventricles: bottom two chambers; fill with blood then contract
to move it along.
Termed “right ventricle” and “left ventricle”.
Valves: prevent blood from moving backward, in the wrong
direction.
Right and left semilunar valves.
Right and left atrioventricular valves.
RIGHT SIDE (Pulmonary)

26. blood will be sent to the lungsLEFT SIDE (Systemic)
blood will be sent to the bodyEnters via vena cavas:
Right atrium
Right atrioventricular valve
Right ventricle
Right semilunar valve
Pulmonary arteries
Lungs
This is where oxygen enters in to the blood
(RBC/hemoglobin).Enters via pulmonary veins:
Left atrium
Left atrioventricular valve
Left ventricle
Left semilunar valve
Aorta
To the rest of the body
THIS ALL HAPPENS IN ONE SINGLE HEART BEAT!
Both atria contract at the same time.
Both ventricles contract at the same time.
Only difference between sides is where blood moves during
contraction!
Blood vessels
Arteries: branch from heart, carry oxygenated blood AWAY
from heart.
Thick walls, withstand high pressure.
Arterioles: “little arteries” still carrying blood AWAY.
Capillaries: form networks in tissues where gas/nutrient
exchange occurs!
Smallest vessels, thinnest walls.
Venules: “little veins” on the other side of capillary networks;
carry blood TOWARD the heart.
Veins: bring deoxygenated blood TOWARD heart.

27. Large in diameter, have one-way valves to make sure blood
moves in one direction!
exception with arteries and veins
The pulmonary arteries and veins we talked about work a little
differently than the rest!
Pulmonary arteries carry DEOXYGENATED blood away from
the heart – this is because they are delivering it to the lungs to
get oxygen in the first place!
Pulmonary veins carry OXYGENATED blood toward the heart
after the lungs have filled it with the gas!
Chapter summary slide #1
Respiratory system brings in oxygen and releases carbon
dioxide.
alveoli in lungs.
Alveoli are “air sacs” that make up the lungs.
They are wrapped in capillaries which are tiny, thin walled
blood vessels.
Gas exchange occurs between these two structures!
Chapter summary slide #2
Diffusion is the movement of molecules from high to low
concentration.
alveoli.
fuses into alveoli from
capillaries (blood).

28. Blood holds red blood cells (hemoglobin for oxygen), white
blood cells and antibodies (immunity and protection from
infection/invaders), platelets (clotting), and nutrients among
other things.
Circulatory system transports blood through body.
Chapter Summary Slide #3
Blood vessels are the path for blood; arteries (away from heart),
arterioles, capillaries (sites of nutrient and gas exchange),
venules, and veins (blood back to heart).
Heart acts as a pump to push blood.
Heart is made of cardiac muscle, is involuntary and pacemaker
cells make its own electricity!
Right side (pulmonary circuit) takes deoxygenated blood from
the heart to the lungs.
Left side (systemic circuit) takes oxygenate blood back to the
heart and then out to the body.
In and out
CORE273 SUMMER2019
Digestive system
Breaks large molecules into smaller molecules that can be
absorbed into the body.
rol and fatty acids.
Water, vitamins, and minerals are also absorbed.
System eliminates solid waste we don’t need.
Hunger and satiety cues

29. Ghrelin hormone says “give me more food!”
Released by stomach.
Increases before meals, decreases after.
Leptin hormone says “I’m full – stop eating!”
Secreted primarily by adipose tissue.
Regulates body weight and energy balance.
Increases in overfed states, decrease in starvation.
We begin at the mouth
Teeth mechanically break down food.
Saliva and amylase (enzyme) chemically break down starch
(carb) into sugar.
Chewed food is called a bolus and is swallowed.
Epiglottis ensures food does not enter airway.
Bolus travels down the esophagus.
Smooth muscle contractions or peristalsis pushes it.
Lower esophageal sphincter controls food at the bottom moving
to the stomach.
The stomach
Stretch of the muscle and presence of protein cause release of
gastric juice containing:
Hydrochloric acid at pH of 2.
Denatures proteins.
Mucus protects stomach from acid.
Pepsin: Enzyme to break down proteins.
Muscle contracts move and churn food.
All the mixing liquifies food into chyme.
Pyloric sphincter controls amount of chyme moving into the
small intestine.

30. The small intestine - Digestion
Remaining digestion occurs in small intestine:
Duodenum (first 10 inches) is where this occurs.
Water and bicarbonate released from pancreas neutralize acid,
and enzymes released from pancreas continue digestion of all
molecule types.
Bile (created in liver; released by gallbladder): helps to
emulsify fats for better absorption.
The Small Intestine - absorption
The final 19 feet of small intestine called the jejunum and the
ileum absorbs nutrients.
95% of absorption takes place in the small intestine.
Absorbed into blood and lymph vessels.
Villi increase surface area to increase absorption rate.
Segmentation of smooth muscle increases rate also.
Ileocecal valve directs remnants from small to the large
intestine (colon).
The large intestine
Absorbs water and creates solid waste.
Certain vitamins and minerals are absorbed as well.
Bacteria help ferment “leftovers” to get some of these.
At the lower end, solid waste is compacted as feces.
Moved through rectum, anus, and then out of the body.
Sphincters in the anus control when feces is eliminated.

31. The urinary system
Kidneys are the primary organ of the urinary system where
urine is produced.
The structural and functional units of the kidneys are nephrons.
Nephrons filter blood and create urine via:
Glomerular Filtration
Tubular Reabsorption
Tubular Secretion
Urine is collected in renal pelvis of kidney and transported via
ureters to the urinary bladder.
Release from the body occurs via the urethra.
Water and sodium
The urinary system closely monitors blood pressure to manage
water and sodium.
LOW BP and HIGH SALT
Indicates not enough water.
Antidiuretic Hormone (from anterior pituitary in brain) makes
kidneys put water back in body.
Concentrated/dark urine is produced.
HIGH BP and LOW SALT
Indicates too much water.
ADH is inhibited; water put in urine and expelled from body.
Dilute/light colored urine is produced.
DIRECT RELATIONSHIP BETWEEN WATER LEVELS,
BLOOD VOLUME AND BLOOD PRESSURE. WHEN ONE

32. GOES UP, SO DO THE OTHERS!
Chapter summary slide #1
Digestive system breaks large molecules into smaller molecules
that can be absorbed.
glycerol and fatty acids.
Also absorb water, vitamins and minerals.
Ghrelin hormone tells you you’re hungry, leptin tells you you’re
full.
Digestion begins in the mouth.
Food is broken down mechanically by teeth, and (starch/carb)
chemically by enzymes in saliva.
Epiglottis blocks food from airway when swallowed.
Peristalsis pushes food down to the stomach.
Chapter Summary slide #2
Gastric juice in stomach contains acid and enzymes to digest
food (protein).
Duodenum of small intestine finishes digestion via enzymes
from pancreas.
Water and bicarbonate from pancreas first need to neutralize
acid.
Bile from gallbladder (but created in liver) helps emulsify fats.
Jejunum and ileum of small intestine finally absorb the
nutrients.
Villi increase surface area to increase absorption rate!
Large intestine absorbs water, vitamins, and minerals; and
creates solid waste.
Bacteria ferment waste to produce even more nutrition.
Chapter summary slide #3

33. Nephrons are the structural and functional units of the kidneys.
Steps of urine creation are glomerular filtration, tubular
reabsorption, and tubular secretion.
Blood pressure and sodium tell the urinary system how to
manage water and sodium.
by making less/concentrated urine.
by making more/dilute urine.
Fit and healthy
Core273 summer2019
The immune system
Helps our bodies determine what should be there and what
should not.
All cells have antigens on their cell membranes.
Major histocompatibility complexes (MHC) show that cells are
“ours”.
if a cell displays something different, it is considered a
pathogen.
Abnormal or cancerous cells
Bacteria and viruses
Fungal infections
Parasitic animals
The Lymphatic system
Extracellular fluid around capillaries in our tissues will be
picked up by lymph vessels.

34. This lymph circulates via these vessels to lymph nodes.
Hold white blood cells to cleanse lymph before it is returned to
our blood stream.
Blood itself cleansed by spleen.
Tonsils/adenoids hold cells to protect throat from infection.
Thymus nurtures immune cells to maturity.
First Line of Defense
Second line of defense
Non-specific defenses – activated no matter what is causing
damage/infection.
Granulocytes: cells with granules carrying chemicals/enzymes.
Neutrophils: “little eaters” phagocytize or “eat” invaders.
Eosinophils: surround parasites and secrete digestive enzymes.
Basophils: responsible for releasing histamines.
Monocytes: “big eaters” that also alert lymphocytes.
Called Macrophages when stationed in tissues.
Dendritic cells: engulf pathogens and antigens for cells to
recognize and attack.
Natural killer cells: attack any cells that have become infected
or abnormal.
Cause cells to undergo apoptosis or “cell suicide”.
Second line of defense

35. Inflammation: basophils release histamines.
Blood vessels dilate and become “leaky”; WBCs come out of
blood, into tissue.
Complement proteins: group of 30 plasma proteins circulating
to aid in responses.
Marking invaders for phagocytes.
Form complexes to damage invading cells.
Interferon: “interferes” with viral reproduction by warning
healthy cells of invaders.
Fever: increase in body temperature
Higher temperatures are difficult for pathogens to survive.
Too high and our bodies can be damaged by denatured proteins;
our systems can fail!
Third line of defense
Antigen-Specific Defenses
Lymphocyte cells activated to fight specific antigens.
B-Cells: develop in the bone marrow.
Produce antibodies.
Memory B-cells
T-Cells: develop in the thymus gland.
Cytotoxic T-cells
Helper T-cells
Suppressor T-cells
Memory T-cells
B-cells and T-cells undergo selection during maturation.
Negative interaction with “self” cells causes apoptosis or
suppression.

36. B-cells and antibodies
B-cells are cloned into memory cells and plasma cells.
Plasma cells: multiply and release antibodies.
Antibodies bind to invaders with matching antigen.
Clump microbes together.
Attract phagocytes to eat pathogens.
Neutralizes pathogens.
Memory cells: saved in tissue for future encounters.
Variations of t-cells
Helper T-Cells: release cytokines.
Stimulate immune responses.
Killer T-Cells: kill cells displaying enemy antigen.
DIFFERENT FROM NATURAL KILLER CELLS!
Natural killers look for “strange” antigens.
Killer T-cells look for a SPECIFIC antigen.
Perforin to poke holes, Granzyme to digest.
Regulator/Suppressor T-Cells: calm the immune response.
Memory cells: stored for future encounters.
Significance of memory cells
Primary Immune Response
Body recognizes foreign antigen.
Lag time of 3-6 days after antigen appears.
Produce and proliferate T-cells and B-cells.
Memory cells formed and saved.
Secondary Immune Response

37. Pathogen re-infects.
Memory B-cells and T-cells activated immediately.
Unnecessary to go through all steps again.
Symptoms may not emerge!
Chapter summary slide #1
The immune system differentiates between “our” cells, and cells
that don’t belong in our bodies.
All cells have antigens on their outer surfaces to identify where
they belong.
Abnormal/cancerous cells, bacteria, viruses, fungal infections,
and parasites are all pathogens.
The lymphatic system circulates lymph fluid and cleanses it
before it goes back into our blood.
First line of defense; tears (wash away microbes, lysozyme kills
bacteria), saliva washes microbes away, skin (physical barrier,
acidic pH, sweat and oil kill bacteria), respiratory tract has
mucus to trap microbes and cilia to sweep mucus away, stomach
acid kills organisms, urine washes microbes away, large
intestine houses normal bacteria to compete with invaders.
Chapter Summary slide #2
Second line of defense; neutrophils (“little eaters”), eosinophils
(parasites), basophils (histamines), monocytes (“big eaters),
natural killer cells (attack abnormal cells).
Interferon interferes with viral reproduction.
Fever is an increase in body temperature to make it difficult for
pathogens to survive.
Third line of defense; B-cells create antibodies that bind to
invaders with matching antigens (clump microbes together,
attract phagocytes, neutralize pathogens).
T-cells can be “helper t-cells” which release cytokines, “killer”

38. or “cytotoxic t-cells” that kill microbes with a specific antigen.
Memory cells are formed to recognize previous invaders if they
come back so the body can fight them off quicker – sometimes
even without symptoms of infection!
Chemical balance
Core273 SUMMER2019
The endocrine system
Directs chemical messengers: hormones.
Hormones come from specialized tissues and endocrine glands.
They function to maintain homeostasis.
They regulate every system of the body!
Hypothalamus and pituitary gland
Hypothalamus controls thirst, fatigue, hunger, body
temperature, etc.
Directs activity of pituitary gland via nervous and endocrine
signals.
Anterior pituitary
Creates and secretes own hormones.
Responds to hypothalamic releasing hormones.
Posterior pituitary
Stores and releases hypothalamic hormones.
Responds to nerve signals from hypothalamus.
Anterior pituitary hormones
Growth hormone (GH): influences growth.
Stimulates protein synthesis, fat breakdown, energy use
(metabolism).

39. Prolactin (PRL): milk production
Target organ is mammary glands.
Adrenocorticotropic hormone (ACTH): activates adrenal cortex.
Outer part of adrenal gland (over kidneys).
AC then produces/secretes own hormones.
Thyroid stimulating hormone (TSH): activates the thyroid
gland.
Gland just below larynx in throat.
Thyroid then produces/secretes own hormones.
Follicle stimulating hormone (FSH): stimulates growth of
egg/sperm.
Luteinizing hormone (LH): stimulates testes/ovaries to in turn
produce testosterone and estrogen (respectively).
Posterior pituitary hormones
Antidiuretic hormone (ADH): saves water at the kidneys.
Stimulates nephron tubules to allow water to move back into
body.
Oxytocin: uterine contractions in females, milk ejection,
bonding.
Targets uterus and mammary glands.
Under certain circumstances, utilizes a positive feedback loop:
when the outcome of the hormone is to cause MORE of what
released it and MORE hormone.
Pineal gland
Synthesizes and secretes melatonin.
Communicates information about light.
Levels are low during the daylight.
Peak during the dark.
Trains biological rhythms.
Regulates release of LH and FSH.
Powerful antioxidant.

40. Higher levels when we’re younger.
Thyroid and parathyroid
Thyroid Gland: releases T3 and T4, as well as Calcitonin.
Thyroxine (T3) and Triiodothyronine (T4): Regulate BMR
Basal Metabolic Rate: rate energy is expended at a baseline.
Calcitonin: lowers blood calcium levels.
Stimulates osteoblasts to put calcium into bone.
Parathyroid Gland: releases Parathyroid hormone.
Parathyroid hormone: raises blood calcium levels.
Stimulates osteoclasts to release calcium from bone.
Opposes calcitonin to maintain balance!
Adrenal cortex
True endocrine gland.
Aldosterone: saves sodium and potassium at kidneys.
Causes tubules to reabsorb them back into the body.
Often synergistic with ADH.
Cortisol: promotes new sugar production and suppresses
inflammation.
Major hormone in stress responses.
Adrenal medulla
Modified nervous tissue.
Epinephrine/Norepinephrine: “Adrenaline”.

41. Roles in metabolism, blood pressure, heart activity.
Sympathetic nervous responses.
Hormone and neurotransmitter.
Sustained impact on body.
Responsible for “fight or flight” responses!
pancreas
Exocrine: secretions via ducts.
What we saw in digestion.
Endocrine: produces hormones.
Insulin: lowers blood glucose (sugar) levels.
Glucagon: raises blood glucose.
Diabetes Mellitus: inability to process glucose in cells.
Type 1: pancreas can’t produce insulin.
Type 2: cells resistant to insulin produced.
Glucose channels closed.
Other important hormones
Digestive Hormones
Gastrin from stomach stimulates production and release of
gastric juice.
Secretin from small intestine stimulates release of water and
bicarbonate from pancreas.
Cholecystokinin from small intestine stimulates release of bile
from gallbladder and enzymes from the pancreas.
Other Organ Hormones
Renin from kidneys increases blood pressure.
Erythropoietin from kidneys will stimulate production of new
red blood cells.
Thymosin and Thymopoietin from the thymus aid in maturing t-

42. cells.
Atrial Natriuretic hormone from the heart decreases blood
pressure.
Chapter summary slide #1
Endocrine system directs hormones from specialized tissues and
endocrine glands to maintain homeostasis.
Hypothalamus controls thirst, fatigue, hunger, body
temperature, etc., and directs the activity of the pituitary gland.
Anterior pituitary hormones: growth hormone (influences
growth), prolactin (milk production), adrenocorticotropic
hormone (activates adrenal cortex), thyroid stimulating hormone
(stimulates the thyroid gland), follicle stimulating hormone
(eggs/sperm), luteinizing hormone (estrogen/testosterone).
Posterior pituitary hormones: antidiuretic hormone (saves water
at the kidneys), oxytocin (uterine contractions, milk ejection).
rhythms, antioxidant.