1.4C Human Body
Problem 1: Brain and body
Nervous System
Central Nervous System (CNS):
Brain
Spinal Cord
Peripheral Nervous System (PNS):
Connects the brain and spinal cord to the rest of the body
Divided in: A) Somatic nervous system
B) Autonomic nervous system
Somatic nervous system:
+ Conscious processes / Controls voluntary muscles (raising up my hand)
+ Conveys sensory information to the CNS / Regulates interaction with external
environment
Autonomic nervous system:
+ Unconscious processes / Controls involuntary muscles (heart rate, sweating,
sexual arousal)
+ Regulates the body’s internal environment (homeostasis)
+ Divided in the: A) Sympathetic nervous system: Expends energy
B) Parasympathetic nervous system: Conserves Energy
Sympathetic nervous system:
+ A network of nerves that prepare the organs for a burst of vigorous activity (fight or
flight), such as increasing breathing and heart rate, and decreasing digestive activity
+ Consists of chains of ganglia just to the left and right of the spinal cord’s central
regions
(Connections back and forth with the spinal cord)
, 1.4C Human Body
Parasympathetic nervous system:
+ Facilitates vegetative, nonemergency responses (rest and digest)
+ Opposite of sympathetic activities
(Increases digestive activity, whereas the sympathetic system decreases)
+ Increases digestive activity, decreases heart rate, promotes sexual arousal
(erection in males)
Spinal Cord
+ Part of the CNS within the spinal column.
+ The spinal cord is a long bundle of nerves and cells that extends from the
lower portion of the brain to the lower back.
+ It carries signals between the brain and the rest of the body.
+ Cell bodies of the motor neurons are inside the spinal cord
+ If the spinal cord is cut at a given segment, the brain loses motor control and
sensation from that segment and below.
Afferent nerves: ( A- arrive )
Carry information from sensory receptors of the skin and other organs to the central
nervous system
Efferent nerves: ( E-end )
Carry motor information away from the central nervous system to the muscles and
glands of the body.
, 1.4C Human Body
Nerve cells
Dendrite: Receive signals from other cells
Cell body: Organizes and keeps the cell functional
Cell membrane: Protects the cells
Axon Hillock: Generates impulse in the neuron
Axon: Transfers signals to other cells and organs
Axon terminal: Forms junctions with other cells
Axon Branches: Passing the signal in different directions
Nodes of Ranvier: Allow diffusion of ions
Presynaptic terminal (Buttons or terminal buttons): Collection of information from
other neurons
Synapses: The locations where the signal is passed to the dendrites of other
neurons or other cells
Myelin sheath: Increases the speed of the signal
Nucleus: Locations of the DNA
, 1.4C Human Body
Brain
Three major divisions:
A) Forebrain
B) Midbrain
C) Hindbrain
Forebrain:
+ Consists of two cerebral hemispheres, one on the left and one on the right
+ Each hemisphere receives sensory information, mostly from the opposite side of
the body
+ Structures of the forebrain:
A) Cerebral cortex
B) Limbic System:
i. Thalamus
ii. Hypothalamus
iii. Amygdala
iv. Hippocampus
C) Pituitary Gland
D) Basal Ganglia
E) Nucleus Basalis
Limbic System:
The limbic system is the part of the brain involved in our behavioural and
emotional responses, especially when it comes to behaviours we need for survival:
feeding, reproduction and caring for our young, and fight or flight responses.
Thalamus:
+ Centre of the forebrain
+ Most sensory information goes first to the thalamus, which processes it and sends
an output to the cerebral cortex.
+ The cerebral cortex sends information back to the thalamus, prolonging and
magnifying certain kinds of input and focusing attention on a particular stimuli.
Problem 1: Brain and body
Nervous System
Central Nervous System (CNS):
Brain
Spinal Cord
Peripheral Nervous System (PNS):
Connects the brain and spinal cord to the rest of the body
Divided in: A) Somatic nervous system
B) Autonomic nervous system
Somatic nervous system:
+ Conscious processes / Controls voluntary muscles (raising up my hand)
+ Conveys sensory information to the CNS / Regulates interaction with external
environment
Autonomic nervous system:
+ Unconscious processes / Controls involuntary muscles (heart rate, sweating,
sexual arousal)
+ Regulates the body’s internal environment (homeostasis)
+ Divided in the: A) Sympathetic nervous system: Expends energy
B) Parasympathetic nervous system: Conserves Energy
Sympathetic nervous system:
+ A network of nerves that prepare the organs for a burst of vigorous activity (fight or
flight), such as increasing breathing and heart rate, and decreasing digestive activity
+ Consists of chains of ganglia just to the left and right of the spinal cord’s central
regions
(Connections back and forth with the spinal cord)
, 1.4C Human Body
Parasympathetic nervous system:
+ Facilitates vegetative, nonemergency responses (rest and digest)
+ Opposite of sympathetic activities
(Increases digestive activity, whereas the sympathetic system decreases)
+ Increases digestive activity, decreases heart rate, promotes sexual arousal
(erection in males)
Spinal Cord
+ Part of the CNS within the spinal column.
+ The spinal cord is a long bundle of nerves and cells that extends from the
lower portion of the brain to the lower back.
+ It carries signals between the brain and the rest of the body.
+ Cell bodies of the motor neurons are inside the spinal cord
+ If the spinal cord is cut at a given segment, the brain loses motor control and
sensation from that segment and below.
Afferent nerves: ( A- arrive )
Carry information from sensory receptors of the skin and other organs to the central
nervous system
Efferent nerves: ( E-end )
Carry motor information away from the central nervous system to the muscles and
glands of the body.
, 1.4C Human Body
Nerve cells
Dendrite: Receive signals from other cells
Cell body: Organizes and keeps the cell functional
Cell membrane: Protects the cells
Axon Hillock: Generates impulse in the neuron
Axon: Transfers signals to other cells and organs
Axon terminal: Forms junctions with other cells
Axon Branches: Passing the signal in different directions
Nodes of Ranvier: Allow diffusion of ions
Presynaptic terminal (Buttons or terminal buttons): Collection of information from
other neurons
Synapses: The locations where the signal is passed to the dendrites of other
neurons or other cells
Myelin sheath: Increases the speed of the signal
Nucleus: Locations of the DNA
, 1.4C Human Body
Brain
Three major divisions:
A) Forebrain
B) Midbrain
C) Hindbrain
Forebrain:
+ Consists of two cerebral hemispheres, one on the left and one on the right
+ Each hemisphere receives sensory information, mostly from the opposite side of
the body
+ Structures of the forebrain:
A) Cerebral cortex
B) Limbic System:
i. Thalamus
ii. Hypothalamus
iii. Amygdala
iv. Hippocampus
C) Pituitary Gland
D) Basal Ganglia
E) Nucleus Basalis
Limbic System:
The limbic system is the part of the brain involved in our behavioural and
emotional responses, especially when it comes to behaviours we need for survival:
feeding, reproduction and caring for our young, and fight or flight responses.
Thalamus:
+ Centre of the forebrain
+ Most sensory information goes first to the thalamus, which processes it and sends
an output to the cerebral cortex.
+ The cerebral cortex sends information back to the thalamus, prolonging and
magnifying certain kinds of input and focusing attention on a particular stimuli.
