Unit 1 Introduction Flashcards
what is physiology?
study of the normal functioning of a living organism and its component part
what are the key concepts that are important to understanding physiology?
-structure and function
-biological energy
-information flow
-homeostasis
what are the levels of living organisms
-chemical (atoms and molecules)
-cellular (neuron, lymphocyte)
-tissue (collection of cells)
-organ (structural unit made of tissues)
-organ system (integrated group of organs)
-organisms (individual form of life)
how is physiology an integrative science
-considers many different levels of organization
-most current research focuses on molecular and cellular level
-how events in single cell influence everything else
how are cells held together
-anchoring junctions
-gap junctions
-tight junctions
what are the 4 tissue types
- epithelial
- connective
- muscle
- neural
what are the 5 types of epithelia
- exchange (rapid exchange of material)
- ciliated (line airways and female reproductive tract)
- secretory (synthesize and release products into the external environment/blood)
- transporting (selective transport of material)
- protective (found on surface of the body)
what does the epithelial do?
-protects the internal environment of the organism
-regulates exchange of material between the external environment and internal environment
-consists of one or more layers of cells connected to one another and to a basal lamina (basement membrane)
what does the connective tissue do?
-provides structural support and barriers (extensive extracellular matrix)
-the EMC contains proteoglycans, collagen, elastin, and fibronectin
what are the 5 types of connective tissue
- loose (elastic tissue)
- dense (strength is the primary function) (tendons )
- adipose (contains adipocytes)
- blood (watery matrix lacking insoluble protein fibers)
- supporting (dense substances) (bone and cartilage)
what does muscle tissue do?
-ability to contract to produce force and movement
what are the 3 types of muscle?
- skeletal (responsible for gross body movement)
- smooth (responsible for influencing the movemnt of substances into/out of/ within the body)
- cardiac (found only in the heart, contraction moves blood through the body)
what does neural tissue do?
-carry information from one part of the body to another
-there is very little EMC in neural tissue
what does neural tissue do?
-carry information from one part of the body to another
-there is very little EMC in neural tissue
what are the 2 types of neural tissue
- neurons (carry information as electrical or chemical signals)
- glial cells (supporting cells for neurons)
what are the organ systems in the human body
- nervous system
- musculoskeletal system
- circulatory system
- respiratory system
- immune system
- endocrine system
- reproductive system
- digestive system
- urinary system
- integumentary system
what is function?
function of a system is the “why”
what is mechanism?
process of a system is the “how”
what is homeostasis?
-the maintenance of a relatively stable internal environment
-involves a series of automatic control mechanisms
-oscillation around a set point (and a set point can change with time)
what is acclimatization?
environmentally induced change in physiological function with no genetic change
what are the four basic mechanisms of how cells communicate?
- gap junctions
- contact dependant signals
- local communication
- long distance communication
explain gap junctions
-direct cell to cell communication
-occurs via protein channels (connexons) between adjacent cells
-found in many cell types
explain contact dependant signal
-interaction between two membrane molecules on two cells
-found in immune cells and during development
explain local communication
-communication with neighbouring cells
-via paracrine and autocrine signals
-chemicals secreted by cells which act on neighbouring cells are known as paracrine signals (immediate vicinity)
-autocrines act on the cell that produces the chemical
explain long distance communication
-responsibility of the nervous and endocrine system
-nervous system uses combinations of chemical and electrical signals (neurohormones, neurotransmitters)
-endocrine system uses chemical signals (hormones)
why do some cells respond to a chemical signal and others do not?
- target cells have various receptor proteins
- only respond to a chemical signal if they have the appropriate receptor
what are receptors?
-usually transmembrane proteins
-usually found in plasma membrane but can be intracellular (cytosoloic or nuclear)
-membrane spanning receptors have 3 main domains
what are the 3 domains of membrane spanning receptors
- extracellular domain (involved in binding the ligand (chemical signals)
- trans membrane domain (hydrophobic)
- intracellular domain (involved in activating the cellular response
receptors vs. chemical signals
-it is the receptor not just the signal the determines the type of response
-any molecule that can bind with the receptor and induce activity will elicit the response
-agonist (mimics primary ligand and activates receptor in the same way (not normal molecule the body produces)
-antagonist (binds to receptor but no longer produces a signal)
what are the steps of a responses to chemical signals
- signalling molecules binds to receptor
- activated receptor interacts with molecules inside the cell to start a signal
- signal is carried to appropriate place inside the cell (signal transduction)
- response occurs
what is reflex control
-the reaction in one or more organs controlled from elsewhere in the body
-can be any long distance path of the nervous and/or endocrine system
what is local control
-the effects are exerted on neighbouring cells
-ex. paracrine control of blood vessel diameter in response to low O2
homeostatic control systems
-stability is result of balance between input and output
-negative feedback returns variable to original condition
-homeostatic systems maintain similarity not constancy
-set points can be reset
-some variables are controlled more closely than others
-most control systems require communication between cells
response loops in reflex control
-start with a stimulus and results in a response
-feedback pathways control the response loop
-3 types of feedback to regulate response loops
what are the 3 types of feedback/control systems to regulate response loops
- negative feedback
- positive feedback
- feedforward control
explain negative feedback
-results in change that opposes or removes the signal thus returning the variable to its original value
-allows for homeostatic control
-keeps system near or at a set point
-oscillation around a set-point
-ex. blood pressure
explain positive feedback
-response sends a signal that reinforces the stimulus
-sends the variable further from set point until an external signal turns the response off
-ex giving birth
explain feedforward control
-anticipatory control
-predicts that change is about to happen which starts the response loop and prevents change
-ex. thought of food
order of response loop
- stimulus
- sensor or receptor
- afferent pathway
- integrating center (CNS)
- efferent pathway
- target or effector
- response
