Unit 2 - Biological Bases of Behavior

neuroanatomy

the study of the parts and functions of neurons

neurons

• individual nerve cells

• make up nervous system

dendrites

• root-like parts of a cell that stretch from the cell body

• grow to make synaptic connections with other neurons

cell body (soma)

contains nucleus and other parts needed for life

axon

wire-like structure ending in the terminal buttons from soma

myelin sheath (Schwann cells)

fatty covering around axon that speeds neural impulses

terminal buttons (term. branches/synaptic knobs)

branched end of the axon that contains neurotransmitters

neurotransmitters

• chemicals contained in there terminal buttons that allow neurons to communicate

• fit into receptor sites on the dendrites

synapse

the space between terminal branches of one neuron and the dendrites of the next neuron

is a neuron’s resting stat positive or negative?

negative with positive ions surrounding it

cell membrane

semi-permeable, prevents ions from mixing

action potential

electric message firing to neuron B

how a neuron fires (3)

1. reaction begins when terminal buttons of neuron A are stimulated and release neurotransmitters into the synapse, neurotransmitters fit into receptor sites on dendrites of B

2. threshold hit, neuron B cell membrane → permeable, + ions flow into cell

3. when electric charge (action potential is reached) gets to terminal buttons, buttons release neurotransmitters into the synapse

True or false: a neuron either fires completely or it does not fire

true

excitatory neurotransmitter

excite the cell into firing

inhibitory neurotransmitter

prevent next cell from firing

what does the synaptic gap contain?

different types of excitatory and inhibitory neurotransmitters

what determines if the neurotransmitters will pass the threshold and fire?

the amount and type of neurot. received on the receptor sites

nervous system

brings information from senses → brain

what do the two wires in our nervous system do?

1. info → brain

2. brain info → muscles

afferent (sensory) neurons

take info from senses → brain

interneurons

take the message from brain/spinal cord → elsewhere in brain or efferent neurons

efferent (motor) neurons

brain info → rest of body

what does the central nervous system (CNS) consist of?

• brain and spinal cord

• all of the nerves housed within bone

spinal cord

• bundle of nerves through center of spine

• transmits info from body → brain

what does the peripheral nervous system (PNS) consist of?

all the other nerves in the body not in bone

what two nervous systems is the PNS broken into?

1. somatic NS

2. autonomic NS

somatic NS

• Voluntary nervous system/muscle movements

• Sends signals from the CNS to skeletal muscle

autonomic NS

• Involuntary NS/automatic

• Can be divided into the sympathetic or parasympathetic divisions

• Sends signals from the CNS to smooth muscle, cardiac muscle, and glands

what is the autonomic NS split into?

1. sympathetic NS

2. parasympathetic NS

sympathetic NS

• Fight or flight

• In charge of emergency situations

• causes an increase in blood pressure and heart rate

parasympathetic NS

• Resting and digesting

• In charge in non-emergency situations

sensory division

• Afferent part of the PNS

• Carries messages to the CNS from sensory receptors

motor division

• Carries messages away from CNS to any effector

• Efferent part of the PNS

when do reflexes occur?

the moment sensory impulses reach the spinal cord

are reflexes an adaptive trait?

yes

endocrine system

• system of glands that secrete hormones that affect biological processes

• controlled in the brain by the hypothalamus

adrenal glands

located in the top of each kidney and release adrenaline → fight or flight

what do ovaries and testies do?

produce sex hormones

basic genetic concepts

• 46 chromosomes in 23 pairs

• genes can be dominant or recessive

DNA

genetic material that makes up chromosomes