Anatomy & Physiology (Part 2)

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2 Overview Endocrine System Skeletal System Muscle System Nervous System

3 Endocrine System A system of glands & organs which produce hormones that biologically alter the function of the body

4 Endocrine System The pituitary gland sits at the base of the brain, just above the brain stem The parathyroid glands are located on the posterior of the thyroid gland The adrenal glands are on top of the kidneys The pancreas is found between the stomach and the small intestine

5 Endocrine System The anterior pituitary stimulates the thyroid gland to release thyroid hormones T3 and T4 Increasing levels of these hormones in the blood result in feedback to the hypothalamus and anterior pituitary to inhibit further signaling to the thyroid gland This is an example of a negative feedback loop

6 Skeletal System Compact Bone Composed of many microscopic cylinders called osteons arranged closely together

7 Skeletal System Spongy Bone Composed of many thread-like process called trabeculae which traverse the bone in many directions Marrow fills the spaces between the trabeculae

8 Skeletal System Axial Skeleton (red) Composed of all the bones which make up the 'trunk' of the body Skull Vertebrae Ribs Sternum

9 Skeletal System Appendicular Skeleton (green) Composed of the appendages Arms Legs Bones which attach the appendages to the axial skeleton (trunk) Pectoral Girdle Scapula Clavicle Pelvic Girdle Os coxa

10 Skeletal System Joints Structural & functional connections between bones Sutures are fibrous joints found only in the skull Cartilaginous joints are bones connected by cartilage, such as between vertebrae Synovial joints are the only joints that have a space or synovial cavity in the joint

11 Muscle System Functions to contract (shorten) The body contains three types of muscle tissue: Skeletal muscle Smooth muscle cells are long and cylindrical multiple nuclei small, dark nuclei are pushed to the periphery of the cell. cells are short, tapered at each end, and have only one nucleus each Cardiac muscle cells are also cylindrical, but short cytoplasm may branch have one or two nuclei in the center of the cell

12 Muscle System Skeletal muscle fiber (cell) is surrounded by a plasma membrane called the sarcolemma, with a cytoplasm called the sarcoplasm Skeletal muscle fiber is composed of many fibrils packaged into orderly units. The orderly arrangement of the proteins in each unit in a fibril, shown as red and blue lines, gives the cell its striated appearance

13 Nervous System Nervous system is excitable Responds rapidly to the slightest stimulus Composed of neurons and neuroglial cells Neurons produce nerve (electrical) impulses when stimulated Neuroglial cells surround and support the activity of neurons

14 Nervous System Neurons Cell body Dendrites Carry information to the cell body Axon Carries information from the cell body to the next neuron

15 Nervous System Central Nervous System Brain Spinal Cord Peripheral Nervous System Spinal Nerves Cranial Nerves Autonomic Nervous System A subset of the peripheral nervous system that controls body functions automatically

16 Nervous System Central Nervous System Brain Cerebral cortex Frontal lobe (planning and movement) Parietal lobe (sensory interpretations) Temporal lobe (hearing) Occipital lobe (sight)

17 Nervous System Central Nervous System Spinal Cord Central gray matter (neuron cell bodies) Peripheral white matter (neuron axons)

18 Nervous System Meninges Three connective tissue layers that surround the brain and spinal cord Dura mater Arachnoid mater Pia mater Protect the CNS from injury

19 Nervous System Peripheral Nervous System Spinal Nerves Paired nerves which exit the spinal cord All 31 pair of spinal nerves help control organ functions, body movements, and help carry sensory information to the brain

20 Nervous System Peripheral Nervous System Cranial Nerves Paired nerves which exit the cranium (skull) Some only help with organ functions and body movements Some only help carry sensory information back to the brain Some do both

21 Nervous System Autonomic Nervous System A subset of the peripheral nervous system that helps control body functions without conscious thought In the autonomic nervous system, a preganglionic neuron (originating in the CNS) synapses to a neuron in a ganglion that, in turn, synapses on a target organ. Activation of the sympathetic nervous system causes release of norepinephrine on the target organ. Activation of the parasympathetic nervous system causes release of acetylcholine on the target organ.