Anatomy & Physiology (Part 2)
Endocrine System● A system of glands &
organs which produce hormones that biologically alter the function of the body
Anatomy & Physiology (Part 2)
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
Anatomy & Physiology (Part 2)
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
Anatomy & Physiology (Part 2)
Skeletal System● Compact Bone
– Composed of many microscopic cylinders called osteons arranged closely together
Anatomy & Physiology (Part 2)
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
Anatomy & Physiology (Part 2)
Skeletal System● Axial Skeleton (red)
– Composed of all the bones which make up the 'trunk' of the body
● Skull● Vertebrae● Ribs● Sternum
Anatomy & Physiology (Part 2)
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
Anatomy & Physiology (Part 2)
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
Anatomy & Physiology (Part 2)
Muscle System● Functions to contract (shorten)● The body contains three types of muscle
tissue: – Skeletal muscle
● cells are long and cylindrical● multiple nuclei● small, dark nuclei are pushed to the periphery of
the cell.
– Smooth muscle● 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
Anatomy & Physiology (Part 2)
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
Anatomy & Physiology (Part 2)
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
Anatomy & Physiology (Part 2)
Nervous System● Neurons
– Cell body
– Dendrites● Carry information to the
cell body
– Axon● Carries information from
the cell body to the next neuron
Anatomy & Physiology (Part 2)
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
Anatomy & Physiology (Part 2)
Nervous System● Central Nervous
System– Brain
● Cerebral cortex– Frontal lobe (planning
and movement)– Parietal lobe (sensory
interpretations)– Temporal lobe (hearing)– Occipital lobe (sight)
Anatomy & Physiology (Part 2)
Nervous System● Central Nervous
System– Spinal Cord
● Central gray matter (neuron cell bodies)
● Peripheral white matter (neuron axons)
Anatomy & Physiology (Part 2)
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
Anatomy & Physiology (Part 2)
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
Anatomy & Physiology (Part 2)
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
Anatomy & Physiology (Part 2)
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.
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