Anatomy Review

1. Anatomy Review Spring 2010

2. Structural Classification of the Nervous System • Central nervous system (CNS) • Brain • Spinal cord • Peripheral nervous system (PNS) • Nerves outside the brain and spinal cord • Spinal nerves • Cranial nerves

3. Nervous Tissue: Neurons Figure 7.4

4. Axonterminal Actionpotentialarrives Axon oftransmittingneuron Vesicles Synapticcleft Receivingneuron Synapse Transmitting neuron Neurotrans-mitter bindsto receptoron receivingneuron’smembrane Vesiclefuses withplasmamembrane Neurotrans-mitter is re-leased intosynaptic cleft Neurotransmittermolecules Synaptic cleft Ion channels Receiving neuron Neurotransmitterbroken downand released Neurotransmitter Receptor Na+ Na+ Ion channel opens Ion channel closes Transmission of a Signal at Synapses • Impulses are able to cross the synapse to another nerve • Neurotransmitter is released from a nerve’s axon terminal • The dendrite of the next neuron has receptors that are stimulated by the neurotransmitter • An action potential is started in the dendrite Figure 7.10, step 7

5. Regions of the Brain • Cerebral hemispheres (cerebrum) • Diencephalon • Brain stem • Cerebellum

6. Regions of the Brain: Cerebrum • Specialized areas of the cerebrum • Primary somatic sensory area • Receives impulses from the body’s sensory receptors • Located in parietal lobe • Primary motor area • Sends impulses to skeletal muscles • Located in frontal lobe • Broca’s area • Involved in our ability to speak • Cerebral areas involved in special senses • Gustatory area (taste) • Visual area • Auditory area • Olfactory area • Interpretation areas of the cerebrum • Speech/language region • Language comprehension region • General interpretation area

7. Regions of the Brain: Diencephalon • Thalamus • The relay station for sensory impulses • Transfers impulses to the correct part of the cortex for localization and interpretation • Hypothalamus • Helps regulate body temperature • Controls water balance • Regulates metabolism • Epithalamus • Houses the pineal body

8. Regions of the Brain: Brain Stem • Pons • Includes nuclei involved in the control of breathing • Medulla Oblongata • Contains important control centers • Heart rate control • Blood pressure regulation • Breathing • Swallowing • Vomiting • Midbrain • Reflex centers for vision & hearing

9. Regions of the Brain: Cerebellum Provides involuntary coordination of body movements Figure 7.16a

10. PNS: Autonomic Functioning • Sympathetic—“fight or flight” • Response to unusual stimulus • Takes over to increase activities • Remember as the “E” division • Exercise, excitement, emergency, and embarrassment • Parasympathetic—“housekeeping” activites • Conserves energy • Maintains daily necessary body functions • Remember as the “D” division • digestion, defecation, and diuresis

11. Effects of the Sympathetic and Parasympathetic Divisions of the ANS Table 7.3 (1 of 2)

12. The Endocrine System • Uses chemical messengers (hormones) that are released into the blood • Hormones control several major processes • Reproduction • Growth and development • Mobilization of body defenses • Maintenance of much of homeostasis • Regulation of metabolism • These hormones regulate the activity of other cells

13. Location of Major Endrocrine Organs Figure 9.3

14. Pituitary Gland • Often called the “master endocrine gland” • 1. Growth hormone (GH)- disorders • Pituitary dwarfism results from hyposecretion of GH during childhood • Gigantism results from hypersecretion of GH during childhood • Acromegaly results from hypersecretion of GH during adulthood • Prolactin(PRL) tropic hormones: stimulate other endocrine glands • 3. Thyroid-stimulating hormone(TSH) • 4. Adrenocorticotropic hormone (ACTH) • 5. Two gonadotropic hormones (FSH) (LH)

15. Hypothalamus • Oxytocin: Stimulates contractions of the uterus during labor, sexual relations, and breastfeeding & Causes milk ejection in a nursing women • Antidiuretic hormone: Inhibits urine production by promoting water reabsorption by the kidneys Thyroid • Thyroid hormone: Major metabolic hormone • Calcitonin: Decreases blood calcium levels causing deposition on bone • Parathyroid Glands: parathyroid hormone (PTH) • Raise calcium levels in the blood

16. Adrenal Glands • Hormones of the Adrenal Cortex (Outer Layer) • 1. Mineralocorticoids (mainly aldosterone) • Produced in outer adrenal cortex • Regulate mineral content in blood • Regulate water and electrolyte balance • Target organ is the kidney • Production stimulated by renin and aldosterone • Production inhibited by atrialnatriuretic peptide (ANP) • 2. Glucocorticoids (including cortisone and cortisol) • Produced in the middle layer of the adrenal cortex • Promote normal cell metabolism • Help resist long-term stressors • Released in response to increased blood levels of ACTH

17. Short term More prolonged Stress Hypothalamus Releasing hormone Nerve impulses Corticotropic cells ofanterior pituitary Spinal cord Preganglionicsympatheticfibers ACTH Adrenalcortex Adrenalmedulla Glucocorticoids Mineralocorticoids Short-termstress response Long-term stress response Catecholamines(epinephrine andnorepinephrine) 1. Increased heart rate 2. Increased blood pressure 3. Liver converts glycogen toglucose and releases glucoseto blood 4. Dilation of bronchioles 5. Changes in blood flowpatterns, leading to increasedalertness and decreaseddigestive and kidney activity 6. Increased metabolic rate • Retention of sodiumand water by kidneys • Increased bloodvolume and bloodpressure 1. Proteins and fatsconverted to glucoseor broken down forenergy 2. Increased bloodsugar 3. Suppression ofimmune system Roles of the Hypothalamus and Adrenal Glands in the Stress Response Figure 9.13, step 13

18. Male Reproductive System • Testes :Each lobule contains one to four seminiferous tubules • Tightly coiled structures; Function as sperm-forming factories • Empty sperm into the rete testis (first part of the duct system) • Sperm travels through the rete testis to the epididymis • Interstitial cells in the seminiferous tubules produce androgens such as testosterone Epididymis Functions to mature and store sperm cells (at least 20 days) Expels sperm with the contraction of muscles in the epididymis walls to the vas deferens Duct deferens Carries sperm from the epididymis to the ejaculatory duct Ejaculation—smooth muscle in the walls of the ductus deferens create peristaltic waves to squeeze sperm forward Vasectomy—cutting of the ductus deferens at the level of the testes to prevent transportation of sperm

19. Female Reproductive System Ovaries : Composed of ovarian follicles (sac-like structures) Each follicle consists of : Oocyte(immature egg) & Follicular cells—surround the oocyte Duct System: Uterine tubes (fallopian tubes): Receive the ovulated oocyte; Provide a site for fertilization; Attach to the uterus Uterus Receives a fertilized egg; Retains the fertilized egg; Nourishes the fertilized egg Vagina Serves as the birth canal; Receives the penis during sexual intercourse Pelvic inflammatory disease (PID) refers to infection of the uterus (womb), fallopian tubes (tubes that carry eggs from the ovaries to the uterus) and other reproductive organs that causes symptoms such as lower abdominal pain. It is a serious complication of some sexually transmitted diseases (STDs), especially chlamydia and gonorrhea. PID can damage the fallopian tubes and tissues in and near the uterus and ovaries. PID can lead to serious consequences including infertility, ectopic pregnancy (a pregnancy in the fallopian tube or elsewhere outside of the womb), abscess formation, and chronic pelvic pain.

20. Formed Elements of Blood • Erythrocytes • Red blood cells (RBCs) Wear out in 100 to 120 days • Main function is to carry oxygen Hemoglobin: Iron-containing protein • Anemia is a decrease in the oxygen-carrying ability of the blood • Sickle cell anemia(SCA) results from abnormally shaped hemoglobin • Polycythemia is an excessive or abnormal increase in the number of erythrocytes • Leukocytes • White blood cells (WBCs) Crucial in the body’s defense against disease • These are complete cells, with a nucleus and organelles • Able to move into and out of blood vessels (diapedesis) • Can move by ameboid motion • Can respond to chemicals released by damaged tissues • Leukocytosis: WBC count above 11,000 leukocytes/mm3; Generally indicates an infection • Leukopenia: Abnormally low leukocyte level; Commonly caused by certain drugs such as corticosteroids and anticancer agents • Leukemia: Bone marrow becomes cancerous, turns out excess WBC • Platelets • Cell fragments; Derived from ruptured multinucleate cells (megakaryocytes) • Needed for the clotting process

21. Blood • Hematopoiesis: • Blood cell formation • Occurs in red bone marrow • Undesirable Clotting • Thrombus: A clot in an unbroken blood vessel • Embolus: A thrombus that breaks away and floats freely in the bloodstream;Canlater clog vessels in critical areas such as the brain • Bleeding Disorders • Thrombocytopenia: Platelet deficiency • Hemophilia: Hereditary bleeding disorder; • Normal clotting factors are missing • Human Blood Groups • Antigens (a substance the body recognizes as foreign) • may be attacked by the immune system • Antibodies are the “recognizers”