Chapter One Part Two  Review of Homeostasis  Levels of Organization  Organization of the Human body  Anatomical Terminology

Homeostasis Questions There is a homeostasis question at each table. Answer the question within your group. Choose a member of your group to report out the answer to the class. You have 5-7mins to complete your questions.

Homeostatic Mechanism Complete the diagram!

Homeostasis Review 2.sci.life.reg.bodycontrol/

Body Control Center Questions What is homeostasis? Body’s attempt to maintain a stable internal environment

What controls human heart rate? Under what conditions does heart rate change? Pacemaker, receptors in circ. system, brain Increase or decrease in oxygen and carbon dioxide levels due to things like exercise or sleep and certain chemicals can cause change.

How is respiration rate controlled? Rate based on levels of carbon dioxide and oxygen. Brain can cause increase or decrease in rate. Can be consciously controlled

Could you hold your breath indefinitely? What would happen? No, when carbon dioxide builds up you lose voluntary control of respiratory muscles. The body is forced to exhale.

In what different ways does the body control temperature? Heat can be exhaled. Blood also carries blood to skin surface. Perspiration carries the most heat away when the water in sweat evaporates.

How does the body maintain a steady level of sugar in the bloodstream? What happens if it is unable to regulate blood sugar? Two hormones control blood sugar- insulin decreases levels and glucagon increases levels. Diabetes

What factors control blood pressure? The amount of blood your heart pumps—how fast it pumps and how forceful each contraction is—is a major factor in determining blood pressure. There are other factors, too. The amount of blood in the body affects pressure, for example (less blood results in lower pressure). Also, the brain can alter the diameter of the vessels, dilating (widening) them to reduce pressure and constricting (narrowing) them to increase pressure. The brain responds to signals it receives from various cells throughout the body; some of these are sensitive to levels of oxygen and carbon dioxide, some to chemicals, and some to blood pressure itself.

How is this Body Control Center Flash Interactive simulation like the self-regulation that goes on in an actual human body? How is it different? Body Control CenterBody Control Center The body must constantly make changes to maintain stability (homeostasis) just like in activity. Even when stability is reached the organism can change activities and cause new changes necessary to maintain stability. In the body many more things are must be regulated. Some of these things can affect other things so multiple changes are actually necessary.

If various physiological responses are constantly adjusting, do you think the body is ever in equilibrium? Why or why not? The body generally is always striving for equilibrium but never quite reach it because conditions are constantly changing.

Levels of Organization in the body:  Atom  Molecule  Macromolecule  Organelles  Cells  Tissue  Organs  Organ Systems  Organism

Anatomical Planes of the Human Body

Anatomical Planes Defined p.14 Fig  Saggital (median) Plane – lengthwise cut of the body into right and left sides; if passes along midline, then body is in equal parts = median  Transverse (horizontal) plane – cut that divides body into superior and inferior portions  Coronal (frontal) plane – divides body into anterior and posterior views.

Anterior and Posterior view

Anterior and Posterior Positions  Anterior –  means towards the front  Posterior –  opposite view of anterior; means toward the back

Superior and Inferior Views

Superior –  means the body part is above another part or is closer to the head. Inferior –  means the body part is below another part or is closer to the feet

Medial and Lateral Views

Medial and Lateral Medial -  relates to an imaginary midline dividing the body into equal left and right halves. Body part is medial if it is close to the midline. (Nose is medial to the eyes) Lateral –  means toward the side with respect to the imaginary midline (Ears are lateral to the eyes)

Proximal and Distal Views

Proximal and Distal Proximal –  describes a body part that is closer to a point of attachment than another body part. (Elbow is proximal to the wrist) Distal –  opposite of proximal; particular body part is farther from a point of attachment than another body part. (Fingers are distal to the wrist)

Superficial and Deep Superficial –  situated near the surface Deep –  parts that are more internal

Body Views Axial Portion – head, neck, trunk  Dorsal cavity – cranial cavity and vertebral canal  Ventral Cavity – Thoracic cavity, Diaphragm, abdominopelvic cavity Appendicular Portion – arms & legs

Body Cavities Lateral View

Body Cavities Coronal View Cranial Spinal/ Vertebral Mediastinum Pleural Pericardial Diaphragm Abdominal Pelvic Abdominopelvic Ventral

Body Cavities cranial cavitiy –  houses the brain vertebral canal –  spinal cord and some vertebrae

Body Cavities Thoracic cavity – Lungs and more  Mediastinum region (separates right and left lungs) = heart, esophagus, trachea, and thymus Diaphragm –  separates the thoracic from the abdominopelvic

Body Cavities  abdominopelvic cavity –  Abdominal cavity – stomach, liver, spleen, gallbladder, kidneys, most of the small and large intestines  Pelvic cavity – enclosed by hip bones; includes terminal portion of large intestine, urinary bladder, and internal reproductive organs.

Head Cavities

 Oral cavity – teeth and tongue  Nasal cavity – within the nose; divided into right and left regions by nasal septum  Sinuses – frontal and sphenoidal sinuses connect to nasal cavity  Orbital cavity – eyes, skeletal muscles, and nerves  Middle Ear Cavity – middle ear bones

There will be a Quiz on Body Views, Cavities, and Regions Review Homeostasis too!