Anatomy & Physiology (Part 2)

Anatomy & Physiology (Part 2)

Overview

Endocrine SystemSkeletal SystemMuscle System

Nervous System

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.