human physiology

Structural organization & Body systems

6 levels

chemical level: involves basic units of matter (atoms+molecules)

E.g transfer of energy through chemical matter

cellular level: comprises individuals cells, vary in type and purpose

E.g red blood cells carrying oxygen

Tissue level: organization of cells with similar structures and functions

e.gmuscle( contracts for movement

organ level: different types of tissue working together to perform specific functions

E.g stomach+the kidneys

system level: consists of a lot of organs that collaborate to carry out broader physiological functions
(Consists of)→ hormone-producing glands and hormone producing cells in numerous organs

E.g cardiovascular system/ muscular system

organismal level: the entire living organism (all systems working together)

BODY SYSTEMS

Most focus

muscular
Nervous
Cardiovascular
Respiratory
Endocrine

NERVUSE SYSTEM

(Consist of) → brain , spinal cord, nerves

Function: generate action potentials to regulate body’s activities (interprets changed to environment

ENDOCRINE SYSTEM

Function: regulates bodies actives by releasing hormones

RESPIRATORY SYSTEM

(Consists of)→ lungs and air passageways

Function: transfers carbon dioxide form blood and exhaled air

CARDIOVASULAR SYSTEM

(Consists of) → blood, heart and blood vessels

Functions: blood carries oxygen and nutrients to cells

MUSCULAR SYSTEM

(Consists of) → skeletal muscle tissue s

Function: helps with body movements + maintains posture

ENERGY SYSTEMS

ATP/PC

-Immediate energy supply proffered fuel=PC stores last < 10s

Anaerobic system

-Intermediary energy supply → preferred fuel= glycogen

Basic Life processes

Metabolism: susms all chemical processes

Responsiveness: Bodies ability to detect and respond to change

Movement: Motion of the whole body

Growth : increase in size of cells

—> If one of these stops working it can lead to death

Aerobic system

-sustained energy supply → preferred fuel = fats & glucose

Differentiation: development of a cell from an unspecialized cell to a cell which is specialized

Reproduction: Formation of new cells by the process of cell division

Homes = sameness ( HOMEOSTASIS)

Stasis = standing still

—> body likes to be static and tightly regulated

Homeostasis : the condition of equilibrium ( balance) in the body’s internal sentiment due to constant interaction of the body’s numerous regulatory processes

A dynamic conditions

balances input with output

—> making sure it’s not too sweet , sour or thick

Fluid within the cell = intercellular fluid

Fluid outside body cells = extra cellular fluid

ECF between cells of tissues = interstitial fluid

(Important )

— what regulates things out of cells

CONTROL OF HOMEOSTASIS

— constantly disrupted internally and externally e.g physiological factor or psychological factor

Disruption can be prolonged

Nervous system and endocrine system =work together to regulate homeostasis

FEEDBACK either negative or positive

NEGATIVE : bringing the response back to normal e.g if the body is hot the body will sweat to cool down (temperature)

POSTIVE: reinforce the change that is detected e.g labor , blood clotting

Afferent parhway : transmits input to the control center (sensory system )

Control center (brain ) : process information ,assess input from receptors

PHYSICAL ACTIVITY & HOMEOSTASIS

→ negative feedback responses

adaptive responses : body needs to shift to match the intern energy demands

Increase breathing = getting more oxygen —> increase respiration

Heart rate and oxygen: when having an increase heart rate allows for greater muscles energy requirements

INORGANIC & ORGANIC COMPOUNDS

Chemical elements (Major elements)

oxygen
Carbon
Hydrogen
Nitrogen

Chemical reactions are the foundation of all life processes —> each chemical reaction involves energy changes

→ potential energy

→ chemical energy → Electrical energy

→ kinetic energy

Types of chemical reactions

1.Anabolism (synthesis reaction): two or more atoms, ions or molecules combine to form new and larger molecules e.g DNA synthesis

Catabolism( Decomposition reaction): Spilt up large molecules into smaller atoms,ions or molecules e.g Lipolysis

Chemical elements

( organic & inorganic)

inorganic compounds lack carbon and are structural simple
Organic compounds always contain carbon and often have hydrogen

INORGANIC COMPOUNDS- Water

→ Solvent: Dissolves waste products, which allows them to be flushed out of the body in the urine

→ Chemical reactions: Synthesis reactions produce larger ,moelcules and release water as a product

→ Lubricant: Facilitates organ movement, joint function and digestion

→ Thermal properties: Able to absorb and release a significant amount of heat with minimal temperature change

SALTS, ACIDS & BASES

Salts (important for bodily fluids)

Salts are important parts of fluids in our body like blood and lymph, they carry out essential chemicals that out body needs to work properly

Acids

-Dissolve in water and release hydrogen ions (H+) and negativity charged anions

Bases (proton donors)

-dissolve in water and release hydroxyl ions (OH-) and positively charged cations

(Proton acceptors)

Acid-Base Balance

The more H+ in a solution = more acidic
The more OH- in a solution = more basic
PH gradients are essential for moving fluids like blood and maintaining cellular functions

ORGANIC COMPOUNDS ( always contain carbon)

→ allows them to carry out complex functions e,g carbohydrates, proteins ,lipids

IMPORTANCE OF CARBON

-Can form four bonds with other elements ( can create complex molecules with diverse structures

-they are extremely stable

Ability or form polymers (Large molecules made up of repeating units

KEY ORGANIC COMPOUNDS

Carbohydrates: provide easily used source of cellular food (soluble to water)
Lipids: provide energy, insulation and protection
Proteins: play a role in growth, repair and maintenance of body tissues, immune function and cell differentiation
Nucleic acids: DNA→ inherited genetic material inside cells + RNA → relays instructions to guide cell synthesis

ATP: transfers energy liberated in exergonic catabolic reactions to power cellular activities that require energy

ENERGY PATHWAYS FOR EXERCISE

nuritent conversion to energy

→ carbs fats and proteins are nutrients that the body covets unto ATP

Fuel sources for expertise

→carbs are the primary fuel for moderate to high intensity exercise

→ fats can sustain low intensity exercise for extended periods

Metabolic pathways

→ATP-CP for short burst

→ glycolysis for high-intensity short duration exercise

Changing fuels sources

→ body shifts from fat to carbohydrate metabolism as exercise intensity increases due to increase oxygen demand

WEEK 2

Human physiology fundamentals II

The plasma membrane

lipid bilayer ( double- layered wall)
Protein ( a gatekeeper, controls what goes in and out of the cell)
Carbohydrates ( acts as a name tag , allows cells to recognize each other)

Plasma membrane function

-barrier controls : allows certain substances to enter and exit

-message reception: acts as receptors and receives signals

-supportive wall:serves as a sturdy barrier matins cells shaped

-Cell ID:helps recognizes from foreign cells

Membrane proteins: determines the function a cell can perform (embedded into the lipid bilayer) - ( peripheral proteins are loosely attached)

→ membrane fluidity: flexibility and mobility of thee lipid molecules (movement of protein within the membrane

(Temperature = the cooler the environment the less fluid the membrane is )

→ membrane permeability: ability of the membrane to allow substances to pass through

BOTH ESSENTIAL FOR REGULATING CELLULAR FUNCTIONS

THE CYTOPLASM

→ All cellular contents between the plasma membrane and the nucleus

(Two primary components)

the cytosol
Organelles

Ribosomes

-carry out mRNA instructions to build cellular material

Lysosomes

-carries dygestive and hydrologic enzymes + helps recycles worn-out cell structures

Endoplasmic reticium

-aids in removal of substances + synthesis glycoproteins (Rough ER) - smooth ER :sythesis fatty acids & steroids

Cilia & flagella

-moves fluid along cells surface

Mitochondria ( powerhouse of the cell)→ helps regulate the lifestyle of the cell (can self replicate in size and number)

The nucleus : Most prominent feature of a cell (determine cell functions and responsibilities)

3 primary function

controls cellular structure
Directs cellular activities
Produces ribosomes

Transport across the plasma membrane

( passive process of transport)

Diffusion:(key element for the plasma membrane) →when the random mixing of particles in a solution occurs (high concentration to low concentration

-factors that influence the diffusion rate across plasma membranes

steepness of the concentration gradient
Temperature
Surface area
Diffusion distance

Simple diffusion: substances move freely through the lipid bilayer e.g oxygen+carbon dioxide

Facilitated diffusion: an integral membrane protein assists a specific substance across the membrane (either carrier-mediated or channel mediates

Osmosis:water moves through selectivity permeable membrane e.g water (only substance)

(Active processes of transport )

→ uses energy to move substances from low to high concentration

primary active transport: directly uses energy to power the movement of substances across the plasma membrane

Secondary active transport: Indriectly uses energy to power the movement of substances across the plasma membrane

→ Antiporters: carry two substances across the membrane in opposite directions

→ symporters: carry two substances across the membrane in the same direction

Transport in vesicles

endocytosis: vesicles detach from the plasma membrane bringing material into cells

(3 TYPES)

→ Reeptor-mediates endocytosis

→phagocytosis

→bulk-phase endocytosis

exocytosis: merging of vesicles within the plasma membrane ( realease material)

(TWO TYPES)

→ cells that release digestive enzymes + hormones

→ nerve cells that release neurotransmittersTWO TYPES)

→ cells that release digestive enzymes + hormones

→ nerve cells that release neurotransmitters

(TYPES OF TISSUE) → 4 types

Epithrlial tissue: cels that are arranged in contunous sheet( multiple layers) → lines body cavities

—> e.g skin

connective tissue: it binds,strengthens and supports, protects,a transport system,stores energy,maintains source of immune response

Connective tissue cells

Proper→ loose→ adipose (FUNCTION): provides reserve food fuel undulates against heat loss
Blood (function): transports respiratory gases nutrients,wastes
Cartilage→hyaline(function):supports and reinforces, serves as a cushion

muscular tissue:produces movement ,maintains posture, generate heats

→ three types

Skeletal

Function: movement, posture,heat production

Location: attached to bones by tendons

Cardiac

Function:pump blood to all party’s of the body

Location: heart wall

Smooth

Function: motion of blood vessels airways

Location:walls of hollow internal structures

→ nerve cell

nervous tissue (two types

Generate and conduct nerve pulses

→Gilal cells

Each organ is composed body systems are composed of 2 or more tissues

E.g heart→ made up of cardiac muscle tissue,connective tissue ,epithelial tissue

CARDIAC MUSCLE tissue → made up muscle fibers within the cell

Central dogma of molecular biology: examples the flow of genetic information

RNA= Helps translate and transcribe info

DNA into DNA = Replication

DNA into RNA = Transcription

RNA into protein = Translation

DNA → RNA → protein

Base pairing

(A = T )

(C = G)

DNA polymerase: unwinds the DNA
Topoisomerase: unwinds DNA
Helicase: breaks apart DNA

(GENE EXPRESSION PART 2)

A gene: function unit of DNA sequences that encode for specific proteins or molecules

Encode proteins = coding genes

Encode molecules=non-coding genes

(Genes need to be transcribed(copied) and translated (decoded into proteins

Parts of a gene

Exon → codes for a specific proteins (protein coding region)

Intron → non protein coding region

Promoter region → initiates or kickstarts our transcription process

TRANSCRIPTION

DNA into messagenger RNA(mRNA) = copied from one language into another

3 steps

Initiation → RNA only erase attached to promoter region of DNA, guided transcription factors

Elongation → New RNA molecules get added complementary to the DNA template strand

Termination → Stop signal regulate by Rho proteins or CG sites

RNA processing

the 5’cap and poly-Atail helps stabilizes the mRNA strand

TRANSLATION

sequence of amino acids make up proteins

→ start & stop codon

3 steps

Initiation: ribosomes assemble around mRNA,tRNA binds to start codon

Elongation:mRNA is read one codon after another and amino acids matching the codon get added by tRNA

Termination: real ease factor recognized stop codon,terminate reaction

At transcription level

→ we have promoter regulation

At RNA processing

→ splicing + degrading of RNA

At Trnalsation

→ start of translation,ribosomes assemble

At post-Translation

→ processing,modification and stability of proteins

Cell signalling

Cell signalling: a way for our cells to communicate (allows to response to changes and regulate cell behavior)

Communicate → response to intracellular changes → respond to extra cellular environment → regulate cell behaviour

Ligand: signal molecule E.g gases,lipids,hormones

→ interacts with a cell by binding itself to a receptor

As the ligand and receptor join together this creates a signal transduction pathway

TYPES OF SIGNALLING

Contact dependent: requires direct contact( through gab junctions)

Autocrine: relapse of signals from a cell that act on itself

Paracrine: relapse of signals that can travel short distance to target cell

Synaptic: relapse of neurotransmitters across synapse(the distance between the neuron and the cell) to target cell

Endocrine: relapse of Hermes into the circulatory system to target distant cells

STEPS OF CELL SIGNALLING

Reception→ signal molecule binds receptor

can only bind to a certain receptor
May change shape when its bound to its ligand

Transduction → intracelualr singalling proteins distribute the signal

Response → effector proteins initiate a response(can be varied) to the signal

MAIN CLASSES OF RECEPTORS

(Four main classes)

ion channels receptors: usually in rapid synaptic signalling
G-Protein-coupled receptors: associate with trimeric ( 3) G proteins

3.emzyme-coupled receptors : Have enzyme activity or associate with an enzyme

4.intracellular receptors

Transduction( signal relay)

involves intracellular signalling molecules (secondary messages)
Regulated by molecular switches (switch from inactive to active)
Important for signal amplification

RESPONSE

-timing and persistence (response can be quick or slow

-sensitivity and range: response can be triggered by low or high concetration

Integration and coordination Response may need combination of signal activation and inhibition

Complexity in signal regulation

phosphorylation: adding a phosphate is turning it on and removing one is turning it off

(protein kinase)→ is what is adding that phosphate group

(Protein phosphate)→ removes phosphate groups

GTP binding:The (GEF) Guanine nucleotide exchange factor turn on the protein & the GAP tuns it off by breaking down the GTP

Scaffold proteins → help organize the process ( have interaction domains , brings together all the molecules to help it work properly)

Postive feedback → response to a signal promotes further signalling ( keeps the signal going)

Negative feedback→ a response to a signale that stops or inhibits further signalling (stop to reduce)

module 1 (metabolism)

First law of thermodynamics: energy is transferred from one state to another

chemical energy
Mechanical energy
Heat:regulates out core temperature
Light
Electcrical
Nuclear

Metabolism: the total of all energy transformations that occur in the body

Fuel ( carbs,fat,protein)

Energy (ATP, ADP+Pi)→ used to fuel the physciolocal functions

Work (Heat) ( physiological functions)

Energy-requiring reaction (requires energy)

(ADP+P,+energy →ATP) → Endergenic

Energy-Yielding reaction (break down atp,split phosphate and it breaks down into endoysion phosphate)

(ATP→ADP+Pi + energy) → exergenic

(Stored chemical energy that links the energy-yielding and energy-requiring function within all cells)

What is ATP:chemical energy that is stored,

It is also

a carbon-nitrogen base(Adenine)
A five-carbon sugar(Ribose)
Three phosphates (Pi)

ATP synthesised(phosphorylation)=energy required

ATP broken down(hydrolysis) = energy

ATP Resynthesis

Direct Phosphorylation

By-product: Coupled reaction of creatine phosphate (CP)

Energy source:Creatine phosphate

Duration: 15 sec

(Oxygen is not used)

Anaerobic pathway

By-product: glycolysis and lactic acid formation

Energy source: glucose

(Oxygen is not used)

Duration:30-40sec

Aerobic pathway

By product: Aerobic respiration

Energy source: Glucose,amino acids

Duration: hours

(Oxygen is required)

ATP & three energy systems

ATP-PC SYSTEM

PC stores = preferred fuel

Immediate energy supply (takes place in the cytoplasm of a muscle cell)

ANAEROBIC GLYCOLYSIS

Glycogen=preferred fuel

Intermediary energy supply (takes place in the cytoplasm)

AEROBIC GLYCOLYSIS

fats/glucose = preferred fuel

Sustained energy supply (takes place in the mitochondria)

—> all systems contribute stimutaneously

Goal= match metabolic demands of homeostasis

Module 2(CHO metabolism)

Fuel for work

→ oxygen efficient fuel (carbs)

→energy rich fuel (fat)

→ used as a last resort (protein)

In the muscle there is stored glycogen and protein

(Fuel for metabolism)

Stage 1: GI tract

Stage 2: Tissue cells

Stage 3: Mitchondira (where energy goes)

Carbs are the only source that can provide energy anaerboically

Excess glucose can be stored as glycogen

Glucose → ATP

Glycolysis

Glyco+glycogen → Lysis = spilt /cleave

(Uses and produces ATP)

BOTH ENERGY REQURING AND YEILDING

STAGE 1 (glycolysis)

Can be anaerobic or aerboic ,it occurs in the cytoplasm

Net gain = 2ATP
Rate-limiting enzyme → Phosphofructokinease

End products = 2 ATP, 2 NADH electron carriers ,2pyruvtae

Stage 2 (Formation of Acetyl coenzyme A)

(No ATP produced directly)

Converts pyuvate→ Acetyl CoA

End products = 2 Aceytal CoA, 2 NADH,2 CO2

Stage 3( The Krebs cycle)

occur in the mirchondrial matirx(it requires xylem to be around)

Rate limiting enzyme = Isocrutrate dehydrogenase

If there is a lot of NADH that means there are using those electrons carriers and need to go through the Karen cycle as bit quicker.

Stimulators = ADP , Ca++. NAD+

Inhibitors = ATP,NADH

End products = 2 ATP. 6 NADH,4 FADH2, 4 CO 2

Stage 4( The electron transport chain

→ occurs in the inner mitochondrial membrane + directly uses oxygen

Works by creating concentration gradient (high hydrogen to low hydrogen)

Stimulators = ADP,P ( if there is a lot of ADP that means it will stimulate the electron transport chain to be more quicker

Inhibitors=if there is a lot of ATP it will slow down the electron transport chain

End product = 26-28 ATP

Module 3 - Fats & protein metabolism

Fat is an energy dense source of fuel (lots of energy from fats)

Fat motabolism

→ Lipolysis (breakdown of stored form of fat) + realeases triggered by increase in circulating epinephrine

(Releases free fatty acids to be broken down so it can be usedd to refuel the musceles) + does not directly produce ATP

Beta-Oxididation: the oxidizing of those fatty acids into a Acetyl-CoA ( breakdown of FFAs)

Ocidisation: The process of removing electron from an atom or molecule (removing the carbon from that molecule)

Overall : it’s the sequence of reactions that “chops” FFA into two carbon fragments

BETA-OXIDSATION

Stimulators= glycogen,Epinephrine

Inhibitors for oxidisation ( insulin :hormone response for storing away glucose)

End product ( for each pair of carbon atoms spilt off

10 ATP in Electron transport chain

1 FADH + 1NADH yields 4 ATP in ETC

PALMITATE (medium chain for fatty acids)

Lipolsysis of palmitate( 16-carbon fatty acid)

It cycles through beta-oxidation 7 times
Each cycle produces 2 FADH2 and 1 NADH+h

(1 palmitate will yield = 106 ATP)

ATP utlizised to activate FFA beta-oxidation

Fat VS CHO metabolism

TIMING

Glycolysis: a rapid process that provides immediate ATP for short-term energy needs

Beta-oxidisation: slower supply sustained energy over a long period of time

ATP YEILD

Glycolysis: a quick but limited amount of ATP

Beta-oxidisation: a much higher ATP yield (up tp 106 ATP) but at a slower rate .

PROTEIN METABOLISM

(Branch chain of amino acids)

Leucine
Isoleucine
Valine

The process of breaking down amino acids

Transamination → the process in which the transfer of NDH2 amino group from an amino acid to keep keto acid

( occurs in both the cytoplasm and the mitochondria

Oxidative demanination → Amoino group is removed and becomes ammonia

( occurs in the mitochondria of liver cells)→ aerobic

Glueconeogensis → process of creating glucose in the liver from non-carbohydrate sources e.g Felig cycle & Cori cycle

Important for maintains blood glucose (and to fuel the nervous system)

Protein metabolism - ATP yield

-each amino acid differes in its ATP yield

-Most amino acid derivatives are ultimately ultiesed as a pyruvate or acetyal CoA