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 Central sulcus Precentral gyrus Postcentral gyrus Parietal lobe Frontal lobe Parieto-occipital sulcus (deep) Lateral sulcus Occipital lobe Temporal lobe Cerebellum Pons Medulla Cerebral cortex oblongata (gray matter) Spinal Gyrus cord Sulcus Cerebral white Fissure matter (a deep sulcus)
Regions of the Brain: Cerebrum Parietal lobe Left cerebral hemisphere Frontal lobe Occipital Temporal lobe lobe Cephalad Cerebellum Brain Caudal stem
Regions of the Cerebrum Central sulcus Primary motor area Primary somatic sensory area Premotor area Gustatory area (taste) Anterior association area Speech/language • Working memory (outlined by dashes) and judgment • Problem Posterior association solving area • Language comprehension Visual area Broca ’ s area (motor speech) Olfactory area Auditory area
Figure 7.14
Longitudinal fissure Association fibers Superior Commissural fibers Lateral (corpus callosum) ventricle Corona Basal nuclei radiata (basal ganglia) Fornix Internal Thalamus capsule Third ventricle Projection Pons fibers Medulla oblongata Figure 7.15
Cerebral hemisphere Corpus callosum Third ventricle Choroid plexus of third ventricle Occipital lobe of cerebral hemisphere Thalamus (encloses third ventricle) Anterior Pineal gland commissure (part of epithalamus) Hypothalamus Corpora quadrigemina Midbrain Optic chiasma Cerebral aqueduct Pituitary gland Cerebral peduncle of midbrain Mammillary body Fourth ventricle Pons Choroid plexus Medulla oblongata Cerebellum Spinal cord (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) Pineal gland (part of epithalamus) Hypothalamus Corpora quadrigemina Midbrain Cerebral aqueduct Cerebral peduncle of midbrain Fourth ventricle
Radiations to cerebral cortex Auditory impulses Visual impulses Descending Reticular formation motor projections to spinal cord Ascending general sensory tracts (touch, pain, temperature) (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 Third ventricle Choroid plexus of third ventricle Occipital lobe of cerebral hemisphere Thalamus (encloses third ventricle) Anterior Pineal gland commissure (part of epithalamus) Hypothalamus Corpora quadrigemina Midbrain Optic chiasma Cerebral aqueduct Pituitary gland Cerebral peduncle of midbrain Mammillary body Fourth ventricle Pons Choroid plexus Medulla oblongata Cerebellum Spinal cord (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 Auditory impulses Visual impulses Descending Reticular formation motor projections to spinal cord Ascending general sensory tracts (touch, pain, temperature) (b) Figure 7.16b
Regions of the Brain: Cerebellum Two hemispheres with convoluted surfaces Provides involuntary coordination of body movements
Cerebral hemisphere Corpus callosum Third ventricle Choroid plexus of third ventricle Occipital lobe of cerebral hemisphere Thalamus (encloses third ventricle) Anterior Pineal gland commissure (part of epithalamus) Hypothalamus Corpora quadrigemina Midbrain Optic chiasma Cerebral aqueduct Pituitary gland Cerebral peduncle of midbrain Mammillary body Fourth ventricle Pons Choroid plexus Medulla oblongata Cerebellum Spinal cord (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 Left atrioventricular valve Fossa ovalis (bicuspid valve) Aortic semilunar valve Right atrioventricular valve (tricuspid 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 Left atrioventricular valve Fossa ovalis (bicuspid valve) Aortic semilunar valve Right atrioventricular valve (tricuspid 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 Ventricles contract, Blood returning 4 1 forcing blood against to the atria puts AV valve flaps. pressure against AV valves; the AV valves are forced 5 AV valves close. open. As the ventricles 2 Chordae 6 fill, AV valve flaps tendineae tighten, hang limply into preventing valve ventricles. flaps from everting into atria. Atria contract, 3 Ventricles forcing additional blood into ventricles. AV valves open; AV valves closed; atrial pressure atrial pressure greater than less than ventricular pressure ventricular pressure Figure 11.6a, step 6
(b) Operation of the semilunar valves Pulmonary Aorta trunk As ventricles 1 As ventricles 2 contract and relax and intraventricular intraventricular pressure rises, pressure falls, blood is pushed up blood flows against semilunar back from arteries, valves, forcing filling the leaflets them open. of semilunar valves and forcing them to close. Semilunar valves closed Semilunar valves open Figure 11.6b, step 2
Capillary beds of lungs where gas exchange occurs Pulmonary Circuit Pulmonary Pulmonary arteries veins Venae Aorta and cavae branches Left atrium Left ventricle Right atrium Heart Right ventricle Systemic Circuit Capillary beds of all body tissues KEY: where gas Oxygen-rich, exchange CO 2 -poor blood occurs Oxygen-poor, CO 2 -rich blood Figure 11.4
Blood Flow to the Brain
The Circle of Willis
Superior vena cava Sinoatrial (SA) node (pacemaker) Left atrium Atrioventricular (AV) node Atrioventricular Right atrium (AV) bundle (bundle of His) Bundle branches Purkinje fibers Interventricular Purkinje fibers septum Figure 11.7
ECG Electrocariogram Sinoatrial node Atrioventricular node QRS complex R Ventricular depolarization Ventricular Atrial repolarization depolarization T P Q S-T P-R Segment Interval S Q-T Interval 0 0.2 0.4 0.6 0.8 Time (s)
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