Unit 7: Tranportation, Respiratory, and Circulatory

What is the job of the cell membrane?

It regulates what goes in and out of the cell

How does the cell membrane control what goes in and out of cells?

security fence with security gates

fence = phospholipids

gates = membrane proteins

The cell membrane is primarily composed of a phospholipid bilayer, where the hydrophobic (water-repelling) tails face inward and the hydrophilic (water-attracting) heads face outward. This structure creates a barrier that allows only certain molecules, like small, nonpolar molecules (e.g., oxygen, carbon dioxide), to pass through freely.

What does cholesterol do in the cell membrane?

stabilizes the membrane

What do carbohydrates do in the cell membrane?

cell-cell recognition (signaling)

Proteins jobs in the cell membrane

-structural support

-recognition

-communication

-transport

How do molecules know which way to go (in or out or cell)

They dont they either

- diffuse down the concentration gradient (passive transport)

or

- get pumped against their gradient by membrane protein pumps (active transport)

Passive transport

- Requires no energy

- molecules move from high to low concentration

Two types of passive transport

simple diffusion and facilitated diffusion

Diffusion

random motion of molecules leads to net movement down their concentration gradient until equilibrium is reached

Simple diffusion

solute moves directly through phospholipids

- works best for small nonpolar molecules like oxygen and carbon dioxide

Facilitated diffusion

- transport through a carrier protein

- needed for larger and or polar molecules

- still diffusion because high to low and no energy

2 variations on facilitated diffusion

Channel proteins: fixed open

Carrier proteins: change shape to help substance through

What if cells need to move solutes against their gradient?

Active transport

Active transport

requires energy (ATP)

- goes through transport proteins (these proteins are often called pumps_

Osmosis

the diffusion of water

- water wants to diffuse down its own gradient

- because water is so abundant in cells the net movement of water will impact cell volume

Aquaporis

channel proteins specific to water

- water is small but polar so to move it quickly we use facilitated diffusion

Describing solutions of different concentrations

when comparing two solutions use these terms

hypertonic - high solutes

hypotonic - low solutes

isotonic - equilibrium

Hypertonic

having a greater concentration of solute than another solution (high solutes)

- water rushes into this solution

Hypotonic

Having a lower concentration of solute than another solution (low solute)

- water leaves this solution

Water intoxication

really high water levels dilute the concentration of essential solutes especially sodium

Bulk transport

- moving substances that are too big for facilitated diffusion

- molecules are moved in or out of the cel by phospholipid vesicles that fuse with the plasma membrane

Endocytosis

- bringing something into the cell

- a piece of cell membrane folds in around the material and pinches off, forming a vesicle

Exocytosis

- large molecules that are manufactured in the cell are released through the cell membrane

What is the purpose of the respiratory system?

- it brings oxygen from the environment into the blood and takes CO from the blood out of the body

- we refer to this as "gas exchange"

The path of air

1) Nostrils and Sinus Cavity

2) Pharynx

3) Larynx

4) trachea, bronchi, bronchioles

5) Alveoli

Nostrils and sinus cavity

-air is warmed, moistened and filtered

Air filtration happens at the ...

macroscopic and microscopic levels

macroscopic - nose hairs and mucus trap particles

microscopic - cilia (tiny hairs) capture and sweep away small particles

Pharynx

- epiglottis should be in the relaxed position

Larynx

vocal cords

- sound is produced when air is forced up the larynx while the vocal cords have tension

Trachea, Bronchi, Bronchioles

ridged, cartilaginous tubes that conduct air to the lungs

Gas exchange in land animals

- from bronchi, air passes to smaller tubes called bronchioles

- air ends up in the little balloons called alveoli (s. alveolus) at the end of the bronchioles

Alveoli

(air sacs/tiny spongy balloons)

- 150 million alveoli are present in one lung

- surrounded by capillaries, gas exchange between the blood and air occurs (each one cell thick)

- walls of alveoli must be moist

Inhalation

- when the diaphragm muscle contracts, it moves down and sucks air in like a vacuum

- diaphragm contracts, moves down (intercostal muscles move up)

- chest volume increases, pressure decreases so air rushes in to equalize pressure

Exhalation

- when the diaphragm muscle relaxes, it moves up and push air out

- diaphragm relaxes, moves up (intercostals move down)

- chest volume decreases, air pressure increases so air goes out to equalize pressure

What makes you feel like you need to breath?

- you detect pH levels in blood, not oxygen

- high CO2 from Carbonic acid lowers blood's pH

- the brain detects this lower pH and you feel the urge to breath

Effects of smoking

- damages cilia, inflames the bronchioles, and damages alveoli

- irritates lining in the bronchioles more mucous produced making airways smaller

- causes less oxygen to be obtained out of each breath

Why do we need a heart and blood?

to deliver nutrients to body cells and to remove waste from body cells

Major parts of the circulatory system

heart, blood vessels, blood

What kinds of things are we transporting to and from cells?

Nutrients - oxygen, sugar, vitamins, minerals

Hormones - Estrogen, testosteron, HGH, insulin, epinephrine

Wastes - CO2, nitrogenous waste, toxins, other byproducts of metabolism

Humans have a ________ circulatory system

closed (most effective)

Heart to lungs

pulmonary circuit

Heart to body

systemic system

Heart Beat

when the heart is relaxed the chambers fill with blood

when cardiac muscle contracts the blood is pushed thorugh

Valves

between the chambers and vessels

closing of teh heart valves causes heartbeat sounds

Atria - atrium to ventricle

Semilunar - between ventricles and arteries

Cardiac cycle

diastole and systole

Diastole

ventricle relaxes - artery snaps back

Relaxation of the heart; heart fills with blood

Systole

ventricle contracts - artery stretches from pressure of blood

contraction of the heart; heart pumps blood out

Mechanics of a heartbeat

contraction starts with the SA node (cardiac pacemaker)

Atria contracts first pushing blood down into the ventricles

ventricles contract bottom to top efficiently move blood into the vessels

myocardial infarction

heart attack

when the heart doesnt get enough oxygen from bloody supply

3 types of blood vessels

arteries, veins, capillaries

Difference between a vein and artery

The direction they are going from the heart:

Viens to the heart: low pressure)

Arteries away from the heart: high pressure

Capillaries

thin-walled site of gas exchange at the end of every artery

-capillaries are the tiniest blood vessels and are the site of exchange between the blood and body cells

- after moving through a capillary bed, blood will return to the heart through the veins

every cell bordered by at least one capillary

Arteries

Made of muscle and thick elastic wall to withstand high pressure

Pressure _____ as arteries branch

drops - is lowest in the capillaries

Veins

thin walls made of muscle and elastic tissue

low pressure so have valves to prevent backflow

skeletal muscle movement aids in return of blood from veins to heart

Blood pressure

always taken from an artery

pressure of blood against artery walls

Upper number = systole (pressure when ventricles contract)

Lower number = diastole (pressure when ventricles relax)

Effects of exercise on heart health

-stronger heart means each beat pumps more blood

-more blood vessels surrounding muscles so they work better and last longer

-more mitochondria in each cel

Blood components

Plasma, red blood cells, white blood cells, and platelets

55% Plasma, 45%-red blood cells, < 1% white + platelets

Plasma

Straw colored liquid portion of blood in which cells are suspended

-primarily water contains proteins, amino acids, glucose etc

red blood cells

carry oxygen via hemoglobin molecule

-non-nucleated

-4-6 million in body lifespan = 120 days

- made in bone marrow

White blood cells

5 types ; lifespan few hours to few days

-function in body defense ; some injest bacteria and pathogens others make antibodies

- made in bone marow

Platelets

small non-nucleated cell fragments; lifespan 8-12 days made in bone marrow

- function in blood clotting (when blood vessel walls break, they send protein signals that make platelets stick together to form a patch)

Hemophelia

too little clotting

Thrombus/heart attack

too much clotting