Introduction to the Body Flashcards
What does the skin allow?
Protection against external factors eg. Abrasions and invading microorganisms
Containment of internal organs and vital substances, helps avoid dehydration
Thermal regulation through evaporation of sweat at skin surface or dilation/constriction of superficial blood vessels
Sensation due to sensory receptors for pressure, pain, proprioception (awareness of body’s position in space), and touch.
Synthesis and storage of vitamin D
What layers is the skin made up of?
Epidermis, dermis and subcutaneous tissue
Explain the properties of the epidermis
The epidermis is a tough and horny superficial layer which acts as protective covering layer. There are no blood vessels or lymphatics in the epidermis. Few nerve endings penetrate the epidermis which are sensitive to heat and touch.
Explain the properties of the dermis
The dermis is a dense layer of collagen and elastic fibers. Contributes to the shade of skin and the way that the collagen pattern runs through the tissue characterises the natural tension and wrinkle lines found in the skin (Langer’s lines). The deep layer of dermis contains hair follicles with arrector muscles which, when contracted, causes the hairs to stand on end and produce goose bumps. (thermoregulation)
What 2 types of sweat gland are found in the dermis and what do they secrete?
apocrine: secretes alkaline solution which bacteria can feed on and produce odour, concentrated in inguen and axilla, becomes active during puberty
merocrine: secretes acidic solution
Explain the composition of the subcutaneous tissue
made up of loose connective tissue and stored fat. Also composed of blood vessels, lymphatic vessels and cutaneous nerves. It makes up for most of body fat so its width is dependent on the individual’s nutritional state. Its locations vary and occur in different areas depending on the sex of the individual. Acts as padding/protection and insulation (part of thermoregulation) keeping the heat in the body’s core.
Explain what bursae is and its function
Bursae are closed sacs of serous membrane. Normally collapsed, with no depth. Walls apposed with thin film of lubricating serous fluid running through. Usually found in locations where friction can occur, bursae allows one structure to move freely over the other. Bursae surrounds many vital organs with the viseral membrane on the organ and the parietal membrane against the cavity wall.
What are the 2 parts of the skeletal system?
axial: bones of head neck and trunk (bones of the centreline)
appendicular: bones of limbs and pelvic girdle
Explain the layers of the trilaminar disc
Ectoderm: contributes to skin and neural tube that becomes spinal cord
Mesoderm: cardiovascular system and cavities
Endoderm: gastro-intestinal and reproductive system
Explain how potential spaces are formed in the trilaminar disc and where they are formed
The trilaminar disc then folds laterally which produces closed off spaces or- body cavities -lined by serous membrane with potential spaces for movement and distension, where organs can grow. Locations are pericardium, pleura (lungs), and peritoneum (gastro-intestinal tract).
What is included in the structural division of the nervous system?
central nervous system (CNS) and the peripheral nervous system (PNS), and the nervous system outside of CNS.
What is included in the functional division of the nervous system?
Somatic nervous system (SNS) and autonomic nervous system (ANS)
Explain the role of neurons and the structure of neurons
They transmit information as electric signals or “action potentials”. They consist of a cell body (soma) with multiple thin and short extensions called dendrites and an axon, covered with myelin or Schwann sheath which carries impulses to and away from the cell body. Neurons are supported by glial cells.
What is included in the CNS and what is it’s function in the nervous system?
The encephalon and spinal cord and are responsible for integrating and coordinating incoming/outgoing signals and carry out higher mental functions such as thinking and learning.
What are the different layers of the CNS?
pia matter, arachnoid matter and dura matter which makes up the meninges.
