1 & 2 - Physiology: Introduction to physiology (homeostasis, cell biology) Flashcards
What is physiology in simple terms?
- Study of how the body functions
- What are the mechanisms that allow body to survive?
What are the levels of organization in the body?
- Chemical (molecules)
- Cellular (ex: a cell in the stomach lining)
- Tissue (ex: the layers of the stomach wall)
- Organ (stomach)
- System (digestive system)
- Organism level (whole body)
What are the basic roles of a cell?
- Cell respiration
- Synthesizes and transport proteins within cell
- Regulate cell reproduction
- Exchanges materials with extracellular environment & respond to changes
Examples of specialized functions:
- Produce and secrete digestive enzymes
- Control muscle contraction
- Nerve cells transmit info
What are the types of tissues?
- Muscle (contracts and generates force)
- Types: Skeletal, Cardiac, Smooth
- Nervous (initiating electrical impulses)
- Found in brain, spinal cord and nerves
- Epithelial (exchanging materials between cell & environ.)
- Types: Epithelial sheets, secretory glands (exocrine, endocrine)
- Connective
- Connects, supports, anchors body parts ex: tendons, bone, blood
What are exocrine and endocrine glands made of?
Epithelial tissue
What are the 11 body systems?
- Circulatory
- Respiratory
- Urinary
- Digestive
- Muscular
- Integumentary, & Immune
- Nervous
- Endocrine
- Reproductive
- Skeletal
*These systems regulate complex processes
What is Homeostasis?
- The ability of a cell/organism to maintain a relatively stable internal environment
- Responds to changes in set point (ex:neg feedback)
- Cells need a stable env to survive
- Cells contribute to maintaining homeostasis
ex: Body temperature, Hormones, Blood glucose levels
What do body-fluid compartments help with?
- They enable exchanges between cells and their env.
How is homeostasis regulated? How do control systems work?
- Thousands of control systems acting together.
- A control system must be able to:
- detect deviations (sensor)
- integrate info with other relevant info (control center)
- make appropriate adjustments (effector)
What are the two kinds of homeostatic control systems?
- Intrinsic controls: local controls that are inherent in an organ
- Extrinsic controls: regulatory mechanisms that happen outside an organ, allows coordination of several organs, accomplished by nervous and endocrine systems
What does feedforward mean? What does feedback mean?
- Feedforward: Response made in anticipation of a change
- Feedback: Response made in response to a change
- Negative feedback opposes a change (ex: low body temp)
- Positive feedback amplifies a change (ex: breast feeding milk excretion)
What is the basic structure of a cell?
Nucleus (hold genetic material, determines nature of cell's proteins) Cytoplasm (contains cell's organelles, structural proteins, vesicles and enzymes) Plasma membrane (encloses the cell)
Made of:
- Water (70-85%)
- Proteins (10-20%), lipids, carbs
- Ions (ex: neural activity)
What are organelles?
- Specialized structures within the cell with specific roles (ex: energy production, protein assembly etc)
What is cellular metabolism? What are two processes that occur in cell metabolism?
All the chem rxns involved in maintaining the living state of the cells and the organism, including synthesis and breakdown of molecules.
- Anabolic processes: those that favour the synthesis of molecules for building organs/tissues
- Catabolic processes: favour breakdown of complex molecules into simpler ones
What is ATP? Where is it produced?
ATP = adenosine thriphosphate
Main energy source in the body
Mitochondria is a major ATP production site
What are the two types of metabolism?
- aerobic (with oxygen)
- anaerobic (w/o oxygen)
What cell activities require energy?
- Synthesis of new chem compounds (proteins)
- Membrane transport
- Mechanical work (ex: contraction of heart muscle)
What does plasma membrane do?
- Controls movements of molecules into and out of cell
- Made of Phospholipid Bilayer
What can cross phospholipid bilayer? What factors impact permeability?
- Lipids can cross
- Water soluble (polar) molecule cannot pass through layer
Factors:
- Relative solubility in lipid
- Size of solute
What are membrane proteins and what are some general examples of them?
- They are proteins embedded into cell membrane
Functions:
- Form water-filled channels
- Carrier molecules
- Membrane-bound enzymes
- Receptor sites
- Cell adhesion molecules
What are the kinds of membrane transport?
- Passive transport (transport along conc. gradient)
2. Active transport (against conc. gradient - needs energy)
What is shown here?
Unassisted Transportation.
- Concentration gradient (chemical driving force) - diffusion of particles
- Electrical gradient (Electrical driving force) - diffusion of ions
Together they make electrochemical driving force.
What factors influence the rate of net diffusion of a substance across a membrane? (5)
What’s the relation between diffusion and osmosis?
Net diffusion of water is known as osmosis
water can easily permeate the plasma membrane even though its polar because its very small
Describe the process here
Describe this process. What if concentration on one side is zero?
- Keeps diffusing until other forces come into play (ex: hydrostatic pressure)
What is tonicity and what are the different kinds (3)?
Tonicity: The effect the solution has on cell volume
Isotonic: Cell volume is constant
Hypotonic: Cell swells
Hypertonic: Cell shrinks
What two factors maintain fluid balance?
- ECF volume: regulate blood pressure, maintaining salt balance
- ECF osmotic concentration: must be regulated to prevent swelling or shrinking
What happens when theres too much free water in ECF?
Excess free water in ECF
- Hypotonic cell (swelling)
If theres a deficiency of water in ECF
- Hypertonic cell (shrinking)
What are ways for non lipid-soluble molecules cross through assisted membrane transport?
- Carrier-mediated transport:
- Can reverse shape so binding sites on either side of membrane can be exposed
- two forms: facilitated diffusion and active transport
- Vesicular transport
What are the two types of carrier-mediated transport?
- Facilitated diffusion:
- Most common, no energy consumed, molecules move from high to low
- Active transport
- Molecules move from low to high, against gradient, uses energy
What is an example of ‘Primary active transport’? pump’?
Na-K pump
- Pumps 3 NA out of cell and pumps 2 K into cell for every 1 ATP hydrolyzed
- maintains resting cell membrane potential
- is 1/3 of cell’s energy expending
What is secondary active transport?
- Active transport across a membrane in which a transporter protein couples the movement of 2 diff substances
ex: glucose
What is Vesicular Transport ?
Active form of membrane transport two forms: 1. Endocytosis - into cell 2. Exocytosis - out of cell -> these are balanced to maintain a const cell volume
What are the three types of cell junctions?
- Desmosomes (helps with contraction in muscles, found in skin, heart, uterus)
- Tight junctions (cell off passageway between two cells, impermeable, found in epithelial tissue)
- Gap junctions (links cells by small tunnels, communicating junctions, ions can pass, found in cardiac and smooth muscle)
