Physiology exam 1

Physios

nature, natural, physical

logy/logia

the study of

physiology

the science of/ study of normal functions of living things

Physiological Processes

Homeostasis, metabolism, growth, reproduction, and response to stimuli.

Levels of Organization

atoms> molecules> organelles> cells> tissues> organs> organ systems> organism

valence (e-)

outer shell electrons

covalent bond

sharing of electrons between atoms; strong bonds

non-polar bond

equal sharing of e- (ex. lipids)

polar bond

non-equal sharing of e- (ex. water)

ionic bond

complete transfer of electrons, relatively weak bond, break in water yielding ions

hydrogen bond

weal but significant attractive forces between a H atom in one molecule and an O or an N atom in another molecule

glucose

the energy molecule in the human body

glycogen

energy storage

starch

plant energy storage

cellulose

structural fiber

phospholipids & cholesterol are

water-insoluble > form cell & organelle membranes

triglycerides (neutral fats)

energy storage lipids

steroids

complex & important

lipids

membranes, nutrient storage and release when needed

integumentary system

skin, hair, nails, glands

what is the role of the integumentary system

first line of defense (protection); regulate body temperature

how the integumentary system is integrated

works with immune, circulatory, and nervous systems to maintain homeostasis and barrier protection

Skeletal system

bones, joints, cartilage, and ligaments

what is the role of the skeletal system?

structural support, protects vital organs, stores calcium and phosphate, blood cell production

how is the skeletal system integrated?

works with muscular system for movement, circulatory via bone marrow and endocrine for calcium regulation

muscular system

skeletal, cardiac and smooth muscles

what is the role of the muscular system

generates movement, maintain posture, and thermogenesis (heat production)

how is the muscular system integrated?

works with the skeletal system for movement, nervous for control, and cardiovascular for pumping blood

Nervous system

brain, spinal cord, nerves, sense organs

what is the role of the nervous system

rapid control system, detects internal/external changes, coordinates responses, maintain communication across systems

how is the nervous system integrated?

regulates the cardiovascular system, respiratory digestive, and endocrine to maintain homeostasis

endocrine system

thyroid, adrenal, pituitary glands, and pancreas

what is the role of the endocrine system

produces hormones that regulate metabolism, growth, reproduction, stress, and blood chemistry

how is the endocrine system integrated?

nervous system (neuroendocrine control), circulatory (hormone transport), and reproductive

cardiovascular system

heart, blood, vessels

what is the role of the cardiovascular system?

transports oxygen, nutrients, hormones, and waste products; maintains blood pressure and perfusion

how is the cardiovascular system integrated?

essential for all systems, respiratory for gas exchange, renal for fluid balance and immune system

respiratory system

nose, pharynx, larynx, trachea, bronchi, and lungs

what is the role of the respiratory system?

provides oxygen, removes CO2, and regulates blood pH

how is the respiratory system integrated?

works with the cardiovascular system for gas transport, nervous system for breathing control, and renal for pH balance

digestive system

mouth, esophagus, stomach, intestines, liver, pancreas

what is the role of the digestive system?

breaks down and absorbs nutrients, eliminates solid waste

how is the digestive system integrated?

works with the circulatory system to deliver nutrients, endocrine for digestive hormones, and excretory for waste removal

urinary system

kidneys, ureters, bladder and urethra

what is the role of the urinary system?

eliminates nitrogenous waste, regulates fluid and electrolytes, regulates blood pressure and pH

how is the urinary system integrated?

works with the cardiovascular system for blood pressure/ volume, respiratory for pH balance, and endocrine for hormonal regulation

Lymphatic/ immune system

lymph nodes, lymph vessels, spleen, thymus, immune cells

what is the role of the lymphatic/ immune system?

returns fluid to circulation, filters pathogens, mounts immune responses

how is the lymphatic/ immune system integrated?

works with the cardiovascular for fluid balance, protects integumentary and respiratory systems against infections

reproductive system

testes, penis, ovaries, uterus, vagina, mammary glands

what is the role of the reproductive system?

produces gametes and hormones, fertilization and development

how is the reproductive system integrated?

works with the endocrine system for hormone control, muscular for childbirth, and urinary for shared anatomy in males

Circulatory/ECF transport as central framework

The extracellular fluid (ECF) and the circulatory system form the organizing backbone of physiology because they are the medium and transport system through which all cells receive what they need and eliminate what they don’t.

Nutrient supply

respiratory, GI, liver, musculoskeletal

Waste removal

lungs, kidneys, GI, liver

Regulation and protection

nervous, endocrine, immune and skin

skeletal muscle

controlled by the somatic system; voluntary

smooth muscle

controlled by the autonomic system; involuntary

cardiac muscle

heart muscle, autorhythmic but affected by the autonomic system; involuntary

intracellular fluid

provides the ionic environment for enzymes, metabolism, and protein function; maintains cell volume and electrical charge

~ 2/3 of total body water; inside cells

K+(potassium): high concentration (main intracellular cation)

Mg2+ (magnesium): moderate concentration, bound to ATP and enzymes

PO43- (phosphate): high concentration, both inorganic and in molecules like ATP, nucleic acids

Proteins (negatively charged): large anions contributing to intracellular negative charge

extracellular fluid

maintains perfusion and nutrient delivery; environment for waste removal; acts as buffer system for pH regulation

~ 1/3 of total body water; plasma (in blood vessels), interstitial fluid (between cells)

Na+ (sodium): main cation

Cl- (chloride) and HCO3- (bicarbonate): main anions

Ca2+: critical signaling ion, higher outside than inside

CO2: transported mainly as HCO3- (buffering system)

oxygen, glucose, fatty acids, and amino acids

homeostasis

stable internal conditions despite external changes; maintained by feedback loops

homeostasis pathway

stimulus> receptor> afferent pathway> integration center> efferent pathway> effector tissue> response

negative feedback

Change → response in opposite direction → restores set point

clinical application: blood pressure regulation, sweating

Ex. ↑ blood glucose → insulin release → ↓ glucose back to normal

detects a deviation and reverses it.

positive feedback

Change → response in same direction → amplifies deviation

intensifies a process until completion

clinical application: clotting cascade, childbirth, nerve action potential

Ex. oxytocin release during labor → stronger contractions → more oxytocin.

blood cirulation

rapid movement in vessels (extracellular fluid transport)

capillary tissue exchange

diffusion into interstitial fluid (extracellular fluid transport)

if compartments are balanced:

cells get nutrients, blood pressure is stable, organs are perfused, and waste is cleared

if compartments are imbalanced

edema, dehydration, electrolyte disturbances, shock, or organ failure can result.

Plasma membrane

Selective barrier, communication

Separates cytoplasm from ECF

Lipid bilayer

lipid bilayer

Phospholipids (most abundant): hydrophilic heads and hydrophobic tails

Barrier to water soluble molecules

nucleus

Stores DNA, surrounded by nuclear envelope with pores (RNA/protein exchange)

Nuclear membrane separates nucleus from cytoplasm

Directs cell growth, maturation, replication, and programmed death

nucleolus

Ribosome synthesis

RNA combines with protein and forms ribosomes which are essential for protein production

endoplasmic reticulum

Rough

• Protein synthesis (ribosomes attached)

Smooth

• Lipid synthesis, detox, calcium storage

Clinical: smooth ER in hepatocytes → drug metabolism (cytochrome P450)

ribosomes

Mix of RNA and proteins

Synthesize new protein molecules

Clinical: antibiotics (tetracyclines and macrolides) target bacterial ribosomes selectively

golgi apparatus

Post-translational modification

Packaging of proteins

Directs proteins to lysosomes, membrane or secretion

Clinical: congenital disorders of glycosylation → multisystem disease

lysosome

Contains hydrolytic enzymes that digest waste and organelles

Vesicles fuse with lysosomes and digest into amino acids, glucose

Clinical: lysosomal storage disease (Tay-Sachs and Gaucher’s)

cytoskeleton

Movement, structure

Made of protein fibers

Microfilaments

• Cell shape and mobility

Intermediate filaments

• Structural support

Microtubules

• Transport highways, mitotic spindle

protoplasm

living substance of a cell

peroxisomes

Contains oxidases and catalase which breaks down fatty acids and toxins

Clinical: Zellweger syndrome - defective peroxisome biogenesis

Without functional peroxisomes, cells cannot process certain fatty acids or produce key lipids, leading to systemic dysfunction — especially in the brain and liver.

secretory vesicles

Store substances as proenzymes (inactive precursors)

a cell keeps enzymes in an inactive form until they’re needed, which protects the cell from damage and allows precise control over enzyme activity

mitochondria

Makes 95% of ATP through oxidative phosphorylation

Location: concentrated in areas of high energy demand

cristae (inner folds) are for increased surface area → more reactions

Energy production and self-replication (contain own DNA and ribosomes and can increase in number when energy demand rises)

• Athlete with their legs

cilia

movement of substances

flagella

sperm mobility

amoeboid motion

WBCs migrate into tissues

DNA

Nucleotide components

• Sugar (deoxyribose), phosphate group, nitrogenous base

Base painting rules

• Adenine pairs with Thymine, Cytosine with Guanine

Runs from 5’ to 3’

46 chromosomes (23 pairs)

RNA

Single stranded

Ribose sugar

Uracil replaces thymine

3 types: mRNA, tRNA, rRNA

• carrying genetic information (mRNA), translating it into protein (tRNA & rRNA), processing RNA, and regulating gene expression

Transcription (DNA to RNA)

Initiation

• RNA polymerase binds to the promoter region of DNA (start of a gene).

• DNA unwinds locally to expose the template strand.

Elongation

• RNA polymerase reads the DNA template strand.

• It builds a single-stranded RNA molecule complementary to DNA.

• In RNA, uracil (U) is used instead of thymine (T).

Termination

• RNA polymerase reaches a termination signal on DNA.

• The newly made RNA strand detaches.

Processing (in eukaryotes)

• Pre-mRNA is modified:

• 5’ cap added

• Poly-A tail added at 3’ end

• Introns removed, exons spliced together → mature mRNA

mRNA Processing

5’ Capping

• A modified guanosine cap is added to the 5’ end.

• Functions:

  • Protects mRNA from degradation.

  • Helps ribosome recognize the start of translation.

3’ Polyadenylation (Poly-A Tail)

• A string of adenine nucleotides (poly-A tail) is added to the 3’ end.

• Functions:

  • Protects mRNA from degradation.

  • Assists in export from the nucleus.

Splicing

• Introns (non-coding regions) are removed.

• Exons (coding regions) are joined together.

• Done by the spliceosome (complex of snRNA + proteins).

Nuclear Export

• Mature mRNA is transported from nucleus to cytoplasm for translation

Translation (mRNA to Protein)

Initiation

• Small ribosomal subunit binds to mRNA start codon (AUG).

• tRNA carrying methionine (anticodon UAC) pairs with the start codon.

• Large ribosomal subunit joins → ribosome is ready.

Elongation

• Ribosome moves along mRNA codon by codon.

• tRNAs bring amino acids matching each codon.

• Amino acids are linked by peptide bonds → forming a growing polypeptide chain.

Termination

• Ribosome reaches a stop codon (UAA, UAG, UGA).

• Release factor binds → polypeptide is released.

• Ribosome disassembles.

mRNA is read in codons (3 bases = 1 amino acid).

tRNAs bring amino acids to the ribosome.

Peptide bonds link amino acids → protein grows.

Stop codon signals completion → protein is released.

Cell reproduction

G1 phase

• cell growth and normal metabolic activities

G2 phase

• preparation for mitosis

M phase

• mitosis and cytokinesis

S phase

• DNA replication occurs

p53 tumor suppressor

Detects DNA damage and halts cell division or triggers apoptosis to prevent cancer development

Endocytosis

Uptake of substances too large for diffusion or active transport

Pinocytosis

• Cell drinking or cell engulfs small amounts of extracellular fluid and dissolved substances into tiny vesicles

• Only for fluids and solutes

phagocytosis

Cell eating or a cell engulfs large particles, bacteria, or cellular debris into vesicles called phagosomes

• For solid particles

Sickle Cell Disease

Demonstrates how protein structure directly determines function - a single amino acid can cause devastating disease

Cellular Differentiation

Cells become specialized for specific functions while maintaining same genetic information

Cell Death

Natural process that keeps you healthy

Skin sheds up to 40,000 dead cells

Billions of cells die in intestine and bone marrow every hour

If cell death malfunctions, leads to loss of homeostasis and disease and death occurs

Apoptosis

Programmed cell death

No inflammation

Phagocytosis or cell eating

Cell shrinkage and fragmentation

Insufficient apoptosis → cancer and autoimmune

Excessive apoptosis → neurodegeneration or ischemic injury

Necrosis

Uncontrolled cell death

Inflammatory changes and loss of cell membrane integrity

Affect surrounding cells and dying cells

Cell swelling and lysis

carcinogenesis

Normal cells transform into malignant cancer cells

Initiation

• DNA damage occurs from carcinogens, radiations, or oxidative stress

Promotion

• Damaged cells proliferate due to growth signals or loss of growth inhibition

Progression

• Additional mutations lead to invasion and metastatic capability

Cell death → pathology

• Dysregulated apoptosis contributes to cancer, neurodegeneration and autoimmune disorders