Bio - Integration of Body Systems

nervous system

consists of neurons that transmit electrochemical impulses, transmitted to specific targets rapidly

endocrine system

consists of endocrine glands that release hormones into the bloodstream, slow response

brain as a central information integration organ

receives info, processes and stores it, and can send signals to effector organs if a response is required

spinal cord for unconscious processes

has the capacity to process info and make decisions, especially reflexes

white matter in spinal cord

myelinated axons and other nerve fibers, convey signals from sensory receptors to the brain and brain to organs

grey matter in spinal cord

cell bodies of motor neurons and interneurons, many synapses that process info and make decisions

sensory neurons

located in skin and sense organs, carry nerve impulses

types of receptors

external (touch, heat, light) or internal (chemoreceptors, stretch receptors, barroreceptors)

primary motor cortex

sends signals via motor neurons to striated muscles in body

striated muscles

used for locomotion and controlling posture

pain reflex arcs

involuntary response to a stimulus, simplest type of coordination

process of a reflex arc

receptors detect stimulus → sensory neurons receive signals → signals are passed to neurons in CNS via long axons → interneurons process signals and pass impulses to other neurons → motor neutrons → effectors carry out response

cerebellum

fine-tunes timing/movement of muscles for contraction and balance

circadian rhythm

24 hour cycle controlled by an internal system, dependent on suprachiasmatic nuclei

suprachiasmatic nuclei

controls secretion of melatonin by pineal gland

epinephrine

hormone that prepares body for vigorous activity, secreted by adrenal glands, increases supply of oxygen and glucose via increase in blood flow

hypothalamus

small region of the brain around the 3rd ventricle, links nervous system to endocrine via pituitary gland

pituitary gland

controls processes by secreting HGH, TSH, LH, FSH, and prolactin from anterior lobe or ADH and oxytocin from posterior lobe

HGH

human growth hormone

TSH

thyroid-stimulating hormone

ADH

antidiuretic hormone

sinoatrial node

pacemaker of heart on right atrium

feedback control of heart rate

receptors detect change in blood pressure and pH, sends signals to medulla oblongata, controls HR via sympathetic or vagus nerve and SAN

feedback control of ventilation rate

stretch receptors detect change in muscles, signals sent to brainstem, ventilation is controlled by a negative feedback mechanism

peristalsis

wave-like contraction and relaxation of muscles in the digestive system, pushing food down the gut

kind of muscle in gut

2 layers of smooth muscle tissue (longitudinal and circular)

circular muscles in gut

constrict gut behind food, preventing food from going back to mouth

longitudinal muscles in gut

moves food along gut

tropisms/tropic responses

differential growth responses to directional stimuli

positive tropism

growth toward stimuli (ex: hydrotropism)

negative tropism

growth away from stimuli (ex: thigmotropism)

phototropism

shoots grow towards highest light intensity

process of phototropism

shoot facing brighter light grows at a slower rate, shoot curves towards light and growth equalizes

auxin

hormone that promotes stem growth by promoting protein pump synthesis that acidifies cell walls

auxin efflux carriers

pumps charged auxin (inside cell) across plasma membrane to cell wall where auxin revers to uncharged state

phytohormones

promote/inhibit growth, promote/inhibit development, responds to stimuli

promotion of cell growth

cell walls are made of microfibrils which are crosslinked with carbs that are influenced by pH, decrease in pH weakens links allowing cell to extend via turgor elongation

protoplast

inside cell/cell membrane

apoplast

cell wall

location of auxin production

produced in shoot tips and transported to roots via phloem

location of cytokinin production

produced in roots and transported into shoots by xylem

function of auxin

stimulates cell division (with cytokinin), enlargement, development, inhibits lateral buds

function of cytokinin

stimulates cell division, enlargement (with auxin), lateral buds, inhibits development of roots

ethylene

hormone responsible for fruit ripening

synchronization

ethylene can initiate ripening of other fruits, for more dispersal

apical meristem

found in tips of roots and shoots; causes primary growth (lengthening), cell division is most rapid

lateral meristem

found at cambium, cause secondary growth (widening), produces bark on trees

apical dominance

auxins in apical meristems promote growth in itself but inhibit growth in axillary buds beneath