IB Biology HL: Biological Coordination and Communication (2)

B3.1 Muscle and Motility (HL); D3.3 Homeostasis; C3.1 Integration of Body Systems

nervous system

receives sensory info through structures called receptors and send motor responses to muscles, resulting in movement (only for animals)

epinephrine (adrenaline)

the hormone adrenal glands secrete when facing stressful situations

fight-or-flight response

allows body to react to a potentially life-threatening situation

endocrine system

consists of glands that respond to chemical signals in the body with the production/release of hormones (only affect activity of specific target cells); present in both animals and plants

hypothalamus

area of the brain that acts as a link between the nervous/endocrine system

glandular cells

produce different hormones that either stimulate hormone release bi pituitary gland, or inhibit this releas

adenopypophysis (anterior pituitary)

glandular front of the lobe of the pituitary gland located at the base of the brain, produces and secretes most of the hormones (ex: FSH, LH)

neurohypophysis (posterior pituitary)

posterior lobe of the pituitary gland, which stores and releases oxytocin and ADH produced in the hypothalamus

sinoatrial (SA) node

the natural pacemaker of the heart

baroreceptors

receptors that detect changes in pressure, located on the arch of the aorta and 2 carotid sinuses

stroke volume

volume of blood pumped out of the heart

chemoreceptors

monitor blood content in capillaries, their cells can release a neurotransmitter that initiates action potentials carried to the medulla oblongata; many located in the tongue for tasting

photoreceptors

located within the retina of the eyes for visual information

thermoreceptors

located in the skin to provide information on temperature changes

mechanoreceptors

specialized sensory receptors that respond to mechanical force such as touch, pressure, vibration, stretch, sound

osmoreceptors

in carotid arteries and hypothalamus of the brain, which sense solutes and the water content of blood

proprioreceptors

in muscles and joints, provide the brain with sense of balance and coordination, especially when the body is moving

spinal nerves

impulses sent in and out of the spinal cord by these 31 paired nerves, which emerge directly from the spinal cord

cranial nerves

the brain’s set of 12 paired nerves that connects various parts of the body to the brain through the brainstem

cerebrum

divided into right and left cerebral hemispheres, and each consists of 4 lobes (frontal, temporal, parietal, occipital) that dominate conscious activities

cerebellum

coordinates voluntary movements, controls balance/equilibrium

brainstem

relays impulses between the cerebrum, cerebellum, and spinal cord; also responsible for most functions associated with the autonomic nervous system; all functions occur at a subconscious level

medulla oblongata

regulates both breathing, blood pressure and heart rate

central nervous system (CNS)

brain and spinal cord

spinal cord

spinal cord controls some unconscious reflexes associated with balance and other skeletal muscle, functions independently of the brain

enteric nervous system (ENS)

a separate nervous system that keeps food moving along the digestive tract

peristalsis

involuntary, wave-like muscle contractions and relaxations that move food contents through the digestive tracts

peristaltic reflex

series of smooth muscle contractions that occur along the entire length of the alimentary canal and keeps the food moving

bolus

round masses of food formed when it moves through the alimentary canal

excitatory neurotransmitters

released by motor neurons to an area of smooth muscle behind the bolus to stimulate smooth muscle contraction, causing the bolus to be pushed alon

inhibitory neurotransmitters

released by motor neurons ahead of the bolus to relax smooth muscle and create open space ahead for the bolus to slide through

white matter

tissue of the spinal cord that contains axons/neurons to carry impulses to/from the brain

grey matter 

butterfly-shaped tissue of the spinal cord that contains neurons and synapses involved in spinal cord integration processes

reflex arc

the pathway of the impulse where the sensory information enters the grey matter of the spinal cord and motor information is immediately sent back out