First one up, the Integumentary System.
The Integumentary System consists of the skin, hair, glands, and nails. It protects us from the external environment. Other functions include sensation, vitamin D production, temperature regulation, and excretion of small amounts of waste products.
The skin is made up of two major tissue layers: epidermis and dermis.
The dermis is dense connective tissue. Collagen and elastic fibers provide structural strength, and the blood vessels of the papillae supply the dermis with nutrients.
Hairs are columns of dead, keratinized epithelial cells. Each consists of a shaft, a root, and a bulb. They have a growth phase and a resting phase.
Sebaceous glands produce sebum which oils the hair and the surface of the skin. Eccrine sweat glands produce sweat which cools the body. Appocrine sweat glands produce an organic secretion that causes body odor when broken down by bacteria
Its functions are to support, to protect, to move, to store, and to produce blood cells.
The Skull consists of 22 bones: 8 forming the braincase and 14 facial bones. The hyoid bone and 6 auditory ossicles are associated with the skull.
Pectoral girdle includes the scapulae and clavicles.
Fibrous joints consist of bones united by fibrous connective tissue. They allow little movement.
Its major functions are:
- movement of the body
- maintenance of posture
- respiration
- production of body heat
- communication
- constriction of organs and vessels
- contraction of heart
The Nervous System is involved in some way in nearly every body function. Some major functions of the Nervous System are:
- receiving sensory input
- integrating information
- controlling muscles and glands
- maintaining homeostasis
- establishing and maintaining mental activity
The nervous system can be divided into two, central nervous system (CNS) and peripheral nervous system (PNS). The former consists of the brain and the spinal cord while the latter consists of all nervous tissue outside the CNS (nerves and ganglia).
Here are its types:
Sense is the ability to perceive stimuli. The senses are the means by which the brain receives information about the environment and the body. Sensation, or perception, is the conscious awareness of stimuli received by sensory receptors. Sensory receptors are sensory nerve endings or specialized cells capable of responding to stimuli by developing action potentials. Several types are:
- Mechanoreceptors (respond to mechanical stimuli)
- Chemoreceptors (respond to chemicals)
- Photoreceptors (respond to light)
- Thermoreceptors (respond to temperature change)
- Nociceptors (respond to stimuli that result in the sensation of pain)
Pain is characterized by a group of unpleasant perceptual and emotional experiences There are two types of pain sensation: (1) localized, sharp, pricking, or cutting pain resulting from rapidly conducted action potentials, and (2) diffuse, burning, or aching pain resulting from action potentials that are propagated more slowly.
Olfaction, or the sense of smell, occurs in response to odorants.