A Heart (The Nerve!) Regions of the Brain Cerebral hemisphere - - PowerPoint PPT Presentation

If I Only Had a Brain…

A Heart ….

(The Nerve!)

(b) Adult brain Cerebral hemisphere Diencephalon Cerebellum Brain stem

Regions of the Brain

Precentral gyrus Central sulcus Frontal lobe Postcentral gyrus Parieto-occipital sulcus (deep) Lateral sulcus Occipital lobe Temporal lobe Cerebellum Medulla

• blongata

Spinal cord Cerebral cortex (gray matter) Gyrus Sulcus Cerebral white matter Fissure (a deep sulcus) Parietal lobe Pons

Regions of the Brain: Cerebrum

Frontal lobe Parietal lobe Temporal lobe Left cerebral hemisphere Occipital lobe Cerebellum Cephalad Caudal Brain stem

Regions of the Brain: Cerebrum

Central sulcus Primary somatic sensory area Gustatory area (taste) Speech/language (outlined by dashes) Posterior association area Visual area Auditory area Primary motor area Anterior association area

• Working memory

and judgment

• Problem

solving

• Language

comprehension Broca’s area (motor speech) Olfactory area Premotor area

Regions of the Cerebrum

Figure 7.14

Figure 7.15

Longitudinal fissure Lateral ventricle Basal nuclei (basal ganglia) Thalamus Third ventricle Pons Medulla oblongata Superior Association fibers Commissural fibers (corpus callosum) Corona radiata Fornix Internal capsule Projection fibers

Figure 7.16a Third ventricle Anterior commissure Hypothalamus Optic chiasma Pituitary gland Mammillary body Pons Medulla oblongata Spinal cord 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 Cerebral aqueduct Cerebral peduncle

• f midbrain

Fourth ventricle Choroid plexus Cerebellum Midbrain (a)

Figure 7.12b

(b) Adult brain Cerebral hemisphere Diencephalon Cerebellum Brain stem

Hypothalamus 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 Cerebral aqueduct Cerebral peduncle

• f midbrain

Fourth ventricle Midbrain

Figure 7.16b

Radiations to cerebral cortex Auditory impulses Descending motor projections to spinal cord Visual impulses Reticular formation Ascending general sensory tracts (touch, pain, temperature) (b)

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

Figure 7.16a Third ventricle Anterior commissure Hypothalamus Optic chiasma Pituitary gland Mammillary body Pons Medulla oblongata Spinal cord 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 Cerebral aqueduct Cerebral peduncle

• f midbrain

Fourth ventricle Choroid plexus Cerebellum Midbrain (a)

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

• rgans

Reticular activating system (RAS)

plays a role in awake/sleep cycles and consciousness

Figure 7.16b

Radiations to cerebral cortex Auditory impulses Descending motor projections to spinal cord Visual impulses Reticular formation Ascending general sensory tracts (touch, pain, temperature) (b)

Regions of the Brain: Cerebellum

Two hemispheres with convoluted

surfaces

Provides involuntary coordination

• f body movements

Figure 7.16a Third ventricle Anterior commissure Hypothalamus Optic chiasma Pituitary gland Mammillary body Pons Medulla oblongata Spinal cord 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 Cerebral aqueduct Cerebral peduncle

• f midbrain

Fourth ventricle Choroid plexus Cerebellum Midbrain (a)

Figure 11.3b Superior vena cava Right atrium Right pulmonary veins Fossa ovalis Right atrioventricular valve (tricuspid valve) Right ventricle Chordae tendineae Inferior vena cava (b) Frontal section showing interior chambers and valves. Aorta Left pulmonary artery Left atrium Left pulmonary veins Pulmonary semilunar valve Left atrioventricular valve (bicuspid valve) Aortic semilunar valve Left ventricle Interventricular septum Myocardium Visceral pericardium Right pulmonary artery

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

Figure 11.3b Superior vena cava Right atrium Right pulmonary veins Fossa ovalis Right atrioventricular valve (tricuspid valve) Right ventricle Chordae tendineae Inferior vena cava (b) Frontal section showing interior chambers and valves. Aorta Left pulmonary artery Left atrium Left pulmonary veins Pulmonary semilunar valve Left atrioventricular valve (bicuspid valve) Aortic semilunar valve Left ventricle Interventricular septum Myocardium Visceral pericardium Right pulmonary artery

Figure 11.5

Right ventricle Muscular interventricular septum Left ventricle

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

• ne another to force a one-way path of

blood through the heart

Figure 11.6a, step 6

(a) Operation of the AV valves Blood returning to the atria puts pressure against AV valves; the AV valves are forced

• pen.

As the ventricles fill, AV valve flaps hang limply into ventricles. Atria contract, forcing additional blood into ventricles. AV valves open; atrial pressure greater than ventricular pressure AV valves closed; atrial pressure less than ventricular pressure Ventricles Chordae tendineae tighten, preventing valve flaps from everting into atria. AV valves close. Ventricles contract, forcing blood against AV valve flaps. 1 2 3 4 5 6

Figure 11.6b, step 2

(b) Operation of the semilunar valves As ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open. As ventricles relax and intraventricular pressure falls, blood flows back from arteries, filling the leaflets

• f semilunar

valves and forcing them to close. Semilunar valves open Semilunar valves closed Pulmonary trunk Aorta 1 2

Figure 11.4

Capillary beds

• f lungs where

gas exchange

• ccurs

Pulmonary veins Aorta and branches Left atrium Left ventricle Heart Systemic Circuit Right atrium Right ventricle Venae cavae Pulmonary arteries Pulmonary Circuit Capillary beds of all body tissues where gas exchange

• ccurs

KEY: Oxygen-rich, CO2-poor blood Oxygen-poor, CO2-rich blood

Blood Flow to the Brain

The Circle

• f Willis

Figure 11.7

Superior vena cava Sinoatrial (SA) node (pacemaker) Atrioventricular (AV) node Right atrium Bundle branches Purkinje fibers Left atrium Atrioventricular (AV) bundle (bundle of His) Purkinje fibers Interventricular septum

Sinoatrial node Atrioventricular node QRS complex Ventricular depolarization Atrial depolarization Ventricular repolarization P-R Interval S-T Segment Q-T Interval 0.2 0.4 0.6 0.8 Time (s) R Q S P T

ECG Electrocariogram

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 &

• xygen

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

• rgans to survive