Physiology

System Integration is dependent on

effective communication between components

• positive/ negative feedbacks

• complex and multifactorial loops and branches

Emergent Properties

sum of body systems of an organism that interact and integrate

integration occurs through 2 processes

• hormonal signaling

• nervous signaling

Nervous signaling is

executed by neurons and done through the transmission of impulses in the nervous system

Hormonal signaling is

executed by the endocrine system and is composed of glands that release hormones

Difference between hormonal and nervous signaling

Describe the integration of epinephrine

The brain is made up of

Cranial Nerves: 12 paired nerves connecting to parts of the body to the brain through brain stem.

What does the brain do

• receive info from sensory receptors in specialized sense organs and receptor cells

• processes info, stores some and sends instructions to parts of the body

cerebellum controls

• skeletal muscle contractions and balance

• timing of contracts

• coordination of movements and maintains posture

• memory based activities

Spinal cord is made up of

31 pairs of spinal nerves that branch off left & right between the vertebrae each to different part of body.

Central nervous system (CNS)

brain and spinal cord located inside vertebral column

Spinal cord has 2 main tissues called

white matter and grey matter

White matter contains

• myelinated axon and nerve fibers that send signals from sensory receptors to brain and from brain to organs

Grey matter contains

cell bodies of motor neurons and interneurons with synapses between these neurons

Synapses in grey matter are used for

processing info and for decision making

is the spinal cord an integrating center

Yes

The spinal cord coordinates

unconscious processes and reflexes

Difference between conscious and unconscious processes

What receptors are involved with conscious response

photo

Leucocyte

type of white blood cell

What is a phagocytes main function

first line of defense once a microorganism breaks the physical barriers of the skin and mucous

Amoeboid movement

when phagocytes squeeze through pores in the walls of capillaries and move to the site of infection

what do phagocytes do

engulf pathogens by endocytosis and digest them using enzymes from lysosomes

Where do phagocytes get digestive enzymes

lysosomes

what happens to infected wounds

attract large number of phagocytes resulting the formation of white liquid called pus

What is a phagocyte

a type of leucocyte

what is a lymphocyte

type of leucocyte

where are lymphocytes found

in the lymph system and contained in the lymph nodes

What do lymphocytes do

produce a specific antibody that destroys a specific pathogen

what is an antibody

a large protein

what is the role of the lymphocytes when a pathogen is present

lymphocytes produce antibodies that work together to produce large clones of cells that produce more antibodies; controls the pathogen and clear infection.

What is an antigen

Glycoproteins and large polysaccharides located on the surface of the pathogen.

what is the role of antigen

help lymphocytes distinguish between “self cells” and “non self cells” by recognizing differences between their molecules and body cells.

what is the immune systems response to antigens

production of specific antibodies by lymphocytes that bind to the antigen

how do antigens bind to antibodies

match specific shapes and chemical properties which does not change unlike enzyme substrate connections

What are the steps required for the interactions between different types of white blood cells

what does immunity depend on

presence of b cells capable of producing an effective antibody

what happens when b lymphocytes are activated

due to the low number b-lymphocytes undergo mitosis to form clones which grow and develop an ER with many ribosomes and a large Golgi apparatus

what does the large golgi apparatus and ribosome allow in b lymphocytes

rapid production of antibodies by protein synthesis

plasma B-cells are

cells that have grown and differentiated for antibody production

what is immunity

ability to eliminate an infectious disease from the body

what do antibodies do

provide immunity to a disease

how long do antibodies provide immunity for

few weeks/ months after being secreted by plasma b cells

what secretes antibodies

plasma b cells

what happens to the plasma b cells that secrete antibodies

gradually lost after an infection is cleared

why are plasma b cells slowly lost after an infection is cleared

the antigens associated with the infection are no longer present

how are b cells in a clone produced

mitosis

what do cloned b cells become

plasma b cells

how long do cloned b cells survive

not long after fufilling role of rapid antibody production

What cells remain after the infection

memory b cells

what are memory b cells

small number of cloned cells that don’t immediately secrete antibodies

what do memory b cells do

remain inactive unless the same pathogen infects the body in which they are activated and respond rapidly

immunity to an infectious disease is due having what 2 factors

• antibodies against the pathogen

• memory cells that allow rapid production of antibody

what is an antibiotic

chemical that inhibits metabolism of microorganisms (prokaryotes)

are antibiotics effective on viruses/non-living pathogens?

no because they lack metabolism and rely on host cells for metabolic pathways like transcription and protein synthesis (drugs cannot target these processes as it would damage the host cell)

antibiotic resistance can be prevented by

exclusion as animal growth stimulants, proper hygiene in hospitals, developing new classes of antibiotics, using only for serious bacterial infections

what is zoonosis

disease transmitted from human to animal (rabies)

how does HIV spread

blood or body fluids (sex without condom, hypodermic needles, transfusion of infected blood)

what does HIV do to the immune system

HIV destroys helper T-cells which reduces antibody production; if the immune system is so ineffective, opportunistic infections arrive and lead to AIDS (acquired immunodeficiency syndrome)

what type of virus is HIV

retrovirus; uses reverse transcriptase to produce DNA copies of its genes from RNA

How does immunization occur

vaccine triggers immunity

what do vaccines contain

• antigen that allow a pathogen to be recognized by the immune system

  OR

• nucleic acid from which antigens can be made

What do antigens from a vaccine do

Stimulate

• primary immune response by activation of t-lymphocytes and b-lymphocytes

• production of plasma cells, thus specific antibodies.

what happens when memory cells are produced

long lasting immunity

what happens in the vaccine triggers memory cells

pathogenic microorganism destroyed by secondary immune response if it enters body

How is heard immunity achieved

when significant proportion of population already contracted a disease or been vaccinated

what is the result of herd immunity

spread of virus or pathogen is impeded as it always encounters people who are already immune.

what happens when herd immunity is reached

new outbreak of disease will decline and disappear

What is cell proliferation

rapid increase in # of cells - division happens faster than cell death

The role of mitosis in cell proliferation

ensures continuity of the genome

what are nerves

sheathed bundle of sensory + motor neurons

outline the reflex arc

receptor cells detect stimulus, sensory neurons carry to CNS interneurons, motor neurons receive via synapses, effector cells

dendrites vs axon

dendrites are short, branched nerve fibres while axons are long singular fibres

what are nerve impulses

electrical signals caused by movement of Na+/K+ ions

resting potential of neuron

-70mV

is the Na/K pump in a neuron’s membrane balanced?

active transport of 3 Na+ out and 2 K+ in

action potential of neuron

+30 mV

what are myelinated fibres?

neurons with Schwann cell coat where impulses jump between nodes of Ranvier; less ATP

how does action potential function?

depolarization as Na+ enters then repolarization as K+ exits

outline depolarization (HL) as voltage changes

voltage-gated Na channels open for Na+ to enter, causing positive feedback to make potential +30mV in all areas (self-propagating)

outline repolarization (HL) as voltage changes

voltage-gated K channels subsequently open, K+ diffuses out until potential is -70mV, Na/K pump re-establishes gradients

what is myelin

layers of phospholipid membrane deposited around nerve fibres

what is a synapse

junction between two cells in nervous system

where are synapses

between sensory receptor cells and neurons, neurons, and neurons and effectors (muscles/glands)

can action potential be sent when resting potential is not restored

no

what is synaptic transmission

release of neurotransmitters carrying signals across fluid gap

how are neurotransmitters released from their vesicles

depolarization of presynaptic neuron causes Ca+ to diffuse into membrane and move vesicles to membrane for exocytosis

what do neurotransmitters do in the cleft

diffuse quickly towards receptors on postsynaptic neuron

what happens when neurotransmitters bind to receptors

ion channels open and Na+ diffuses down gradient into post neuron; changes potential

what is an excitatory postsynaptic potential

increased potential; triggers action potential which propagates away from synapse if strong

what is acetylcholine

neurotransmitter

what is acetylcholinesterase

enzyme in cleft that separates acetate and choline

what happens to acetylcholine after transmission

broken down and choline reabsorbs into pre neuron to combine with acetyl group

what are G-Protein-coupled receptors

group of transmembrane receptors; conveys signals to G proteins

what does guanosine diphosphate (GDP) do

binds to secondary G protein in membrane; deactivates

what happens when a ligand binds to receptor

changes receptor shape and GDP detaches for GTP to replace it

what happens when GTP binds to G protein

activates G protein which then disassociates from receptor

what does the G protein do

once dissociated, it triggers cell response to signal

Define Circadian rhythms

• rhythms in behaviour that fit the 24 hour cycle.

• Controlled by an internal system