If I Only Had a Brain…
A
Heart
….
(The Nerve!)
Regions of the Brain
Cerebral
hemisphere
Diencephalon
Cerebellum
Brain stem
(b) Adult brain
Regions of the Brain: Cerebrum
Precentral
gyrus
Central sulcus
Postcentral gyrus
Parietal lobe
Frontal lobe
Parieto-occipital
sulcus (deep)
Lateral sulcus
Occipital lobe
Temporal lobe
Cerebellum
Pons
Medulla
oblongata
Cerebral cortex
(gray matter)
Gyrus
Sulcus
Fissure
(a deep sulcus)
Cerebral
white
matter
Spinal
cord
Regions of the Brain:Parietal
Cerebrum
lobe
Left cerebral
hemisphere
Frontal
lobe
Occipital
lobe
Temporal
lobe
Cephalad
Caudal
Brain
stem
Cerebellum
Regions of the Cerebrum
Primary motor area
Premotor area
Central sulcus
Primary somatic sensory
area
Anterior
association area
Gustatory area (taste)
• Working memory
and judgment
Speech/language
(outlined by dashes)
• Problem
solving
Posterior association
area
• Language
comprehension
Broca’s area
(motor speech)
Olfactory
area
Visual area
Auditory area
Figure 7.14
Longitudinal fissure
Lateral
ventricle
Basal nuclei
(basal
ganglia)
Superior
Association fibers
Commissural fibers
(corpus callosum)
Corona
radiata
Fornix
Thalamus
Internal
capsule
Third
ventricle
Pons
Projection
fibers
Medulla oblongata
Figure 7.15
Cerebral hemisphere
Corpus callosum
Choroid plexus of third
ventricle
Occipital lobe of
cerebral hemisphere
Thalamus
(encloses third ventricle)
Pineal gland
(part of epithalamus)
Corpora
quadrigemina
Midbrain
Cerebral
aqueduct
Third ventricle
Anterior
commissure
Hypothalamus
Optic chiasma
Pituitary gland
Mammillary body
Pons
Medulla oblongata
Spinal cord
Cerebral peduncle
of midbrain
Fourth ventricle
Choroid plexus
Cerebellum
(a)
Figure 7.16a
Cerebral
hemisphere
Diencephalon
Cerebellum
Brain stem
(b) Adult brain
Figure 7.12b
Cerebral hemisphere
Corpus callosum
Choroid plexus of third
ventricle
Occipital lobe of
cerebral hemisphere
Thalamus
(encloses third ventricle)
Hypothalamus
Pineal gland
(part of epithalamus)
Corpora
quadrigemina
Cerebral
aqueduct
Cerebral peduncle
of midbrain
Fourth ventricle
Midbrain
Radiations
to cerebral
cortex
Visual impulses
Reticular formation
Ascending general sensory
tracts (touch, pain, temperature)
Auditory
impulses
Descending
motor projections
to spinal cord
(b)
Figure 7.16b
Regions of the Brain:
Diencephalon
 Thalamus
 Surrounds the third ventricle
 The relay station for sensory
impulses
 Transfers impulses to the correct
part of the cortex for localization
and interpretation
Regions of the Brain:
Diencephalon
 Hypothalamus
 Under the thalamus
 Important autonomic nervous system
center
 Helps regulate body temperature
 Controls water balance
 Regulates metabolism
 Houses the limbic center for emotions
 Regulates the nearby pituitary gland
 Produces two hormones of its own
Regions of the Brain:
Diencephalon
 Epithalamus
 Forms the roof of the third ventricle
 Houses the pineal body (an
endocrine gland)
 Includes the choroid plexus—forms
cerebrospinal fluid
Regions of the Brain: Brain
Stem
 Attaches to the spinal cord
 Parts of the brain stem
 Midbrain
 Pons
 Medulla oblongata
Cerebral hemisphere
Corpus callosum
Choroid plexus of third
ventricle
Occipital lobe of
cerebral hemisphere
Thalamus
(encloses third ventricle)
Pineal gland
(part of epithalamus)
Corpora
quadrigemina
Midbrain
Cerebral
aqueduct
Third ventricle
Anterior
commissure
Hypothalamus
Optic chiasma
Pituitary gland
Mammillary body
Pons
Medulla oblongata
Spinal cord
Cerebral peduncle
of midbrain
Fourth ventricle
Choroid plexus
Cerebellum
(a)
Figure 7.16a
Regions of the Brain: Brain
Stem
 Midbrain
 Mostly composed of tracts of nerve
fibers
 Has two bulging fiber tracts—
cerebral peduncles
 Has four rounded protrusions—
corpora quadrigemina
 Reflex centers for vision and hearing
Regions of the Brain: Brain
Stem
 Pons
 The bulging center part of the brain
stem
 Mostly composed of fiber tracts
 Includes nuclei involved in the
control of breathing
Regions of the Brain: Brain
Stem
 Medulla oblongata
 The lowest part of the brain stem
 Merges into the spinal cord
 Includes important fiber tracts
 Contains important control centers
 Heart rate control
 Blood pressure regulation
 Breathing
 Swallowing
 Vomiting
Regions of the Brain: Brain
Stem
 Reticular Formation
 Diffuse mass of gray matter along
the brain stem
 Involved in motor control of visceral
organs
 Reticular activating system (RAS)
plays a role in awake/sleep cycles
and consciousness
Radiations
to cerebral
cortex
Visual impulses
Reticular formation
Ascending general sensory
tracts (touch, pain, temperature)
Auditory
impulses
Descending
motor projections
to spinal cord
(b)
Figure 7.16b
Regions of the Brain:
Cerebellum
 Two hemispheres with convoluted
surfaces
 Provides involuntary coordination
of body movements
Cerebral hemisphere
Corpus callosum
Choroid plexus of third
ventricle
Occipital lobe of
cerebral hemisphere
Thalamus
(encloses third ventricle)
Pineal gland
(part of epithalamus)
Corpora
quadrigemina
Midbrain
Cerebral
aqueduct
Third ventricle
Anterior
commissure
Hypothalamus
Optic chiasma
Pituitary gland
Mammillary body
Pons
Medulla oblongata
Spinal cord
Cerebral peduncle
of midbrain
Fourth ventricle
Choroid plexus
Cerebellum
(a)
Figure 7.16a
Superior vena cava
Aorta
Left pulmonary artery
Right pulmonary artery
Left atrium
Right atrium
Left pulmonary veins
Right pulmonary
veins
Pulmonary semilunar valve
Fossa ovalis
Right atrioventricular
valve (tricuspid valve)
Left atrioventricular valve
(bicuspid valve)
Aortic semilunar valve
Left ventricle
Right ventricle
Chordae tendineae
Interventricular septum
Inferior vena cava
Myocardium
Visceral pericardium
(b) Frontal section showing interior chambers and valves.
Figure 11.3b
The Heart: Chambers
 Right and left side act as separate
pumps
 Four chambers
 Atria
 Receiving chambers
 Right atrium
 Left atrium
 Ventricles
 Discharging chambers
 Right ventricle
 Left ventricle
Superior vena cava
Aorta
Left pulmonary artery
Right pulmonary artery
Left atrium
Right atrium
Left pulmonary veins
Right pulmonary
veins
Pulmonary semilunar valve
Fossa ovalis
Right atrioventricular
valve (tricuspid valve)
Left atrioventricular valve
(bicuspid valve)
Aortic semilunar valve
Left ventricle
Right ventricle
Chordae tendineae
Interventricular septum
Inferior vena cava
Myocardium
Visceral pericardium
(b) Frontal section showing interior chambers and valves.
Figure 11.3b
Left
ventricle
Right
ventricle
Muscular
interventricular
septum
Figure 11.5
The Heart: Valves
 AV valves
 Anchored in place by chordae tendineae
(“heart strings”)
 Open during heart relaxation and closed
during ventricular contraction
 Semilunar valves
 Closed during heart relaxation but open
during ventricular contraction
 Notice these valves operate opposite of
one another to force a one-way path of
blood through the heart
(a) Operation of the AV valves
1 Blood returning
to the atria puts
pressure against
AV valves; the AV
valves are forced
open.
4 Ventricles contract,
forcing blood against
AV valve flaps.
2 As the ventricles
fill, AV valve flaps
hang limply into
ventricles.
6 Chordae
tendineae tighten,
preventing valve
flaps from everting
into atria.
3 Atria contract,
forcing additional
blood into ventricles.
AV valves open;
atrial pressure
greater than
ventricular pressure
5 AV valves close.
Ventricles
AV valves closed;
atrial pressure
less than
ventricular pressure
Figure 11.6a, step 6
(b) Operation of the semilunar valves
Pulmonary
trunk
1 As ventricles
contract and
intraventricular
pressure rises,
blood is pushed up
against semilunar
valves, forcing
them open.
Semilunar valves open
Aorta
2 As ventricles
relax and
intraventricular
pressure falls,
blood flows
back from arteries,
filling the leaflets
of semilunar
valves and forcing
them to close.
Semilunar valves closed
Figure 11.6b, step 2
Capillary beds
of lungs where
gas exchange
occurs
Pulmonary Circuit
Pulmonary
arteries
Pulmonary
veins
Aorta and
branches
Venae
cavae
Left
atrium
Left
ventricle
Right
atrium
Heart
Right
ventricle
Systemic Circuit
KEY:
Oxygen-rich,
CO2-poor blood
Oxygen-poor,
CO2-rich blood
Capillary
beds of all
body tissues
where gas
exchange
occurs
Figure 11.4
Blood Flow to the Brain
The Circle
of Willis
Superior
vena cava
Sinoatrial (SA)
node (pacemaker)
Left atrium
Atrioventricular
(AV) node
Right atrium
Atrioventricular
(AV) bundle
(bundle of His)
Bundle branches
Purkinje fibers
Purkinje fibers
Interventricular
septum
Figure 11.7
ECG Electrocariogram
Sinoatrial
node
Atrioventricular
node
QRS complex
R
Ventricular
depolarization
Ventricular
repolarization
Atrial
depolarization
T
P
Q
P-R
Interval
0
S
0.2
S-T
Segment
Q-T
Interval
0.4
Time (s)
0.6
0.8
Cardiac Output
 Stroke Volume x Heart Rate
 Avg: 70 ml/beat x 72 beats/min =
5020 ml/ min
 MUST be equal from both
chambers
 Congestive Heart Failure
Homeostatic Imbalances
 Tachycardia: abnormally fast heart
rate (>100 bpm)
 If persistent, may lead to fibrillation
 Bradycardia: heart rate slower than
60 bpm
 May result in grossly inadequate blood
circulation
 May be desirable result of endurance
training
The Heart: Regulation of
Heart Rate
 Increased heart rate
 Sympathetic nervous system
 Crisis
 Low blood pressure
 Hormones
 Epinephrine
 Thyroxine
 Exercise
 Decreased blood volume
The Heart: Regulation of
Heart Rate
 Decreased heart rate
 Parasympathetic nervous system
 High blood pressure or blood
volume
 Decreased venous return
Heart Affects the Brain
 Oxygen delivery
 CHF – can lead to hypoxia
Brain Affects Heart
 Cardiovascular centers in
medulla oblongata
 Cardioacceleratory center
 Cardioinhibitory center
Nerves
 Carotid sinuses monitor pressure
& oxygen
 Via Glossopharyngeal nerve (CN
IX)
 Medulla integration of pressure &
oxygen
Nerves
 Vagus nerve sends inhibitory
impulses
 Sympathetic nerves send
acceleratory impulses
To Make It All Work…
 The heart provides the oxygenated
blood to the brain
 The brain keeps the oxygen flowing
by regulating the heart rate &
strength of contraction
 The nerveprovide constant
communication between the two
organs to survive