1. For each of the following selected tissues, name the tissue type and give a brief description of its specific function:
a) Adipose tissue – (connective tissue) A type of connective tissue that contains stored cellular fat, serves as a source of energy; it also cushions and insulates vital organs.
b) Endocrine gland – (Epithelial Tissue) Any of various glands producing hormonal secretions that pass directly into the bloodstream. The endocrine glands include the thyroid, parathyroids, anterior and posterior pituitary, pancreas, adrenals, pineal, and gonads
c) Cardiac muscle – (muscle tissue) A type of muscle tissue that is found only in the heart and is distinguishable from the two other forms of muscle, smooth muscle (that moves internal organs, such as the bowels, and vessels, such as the artery walls) and skeletal muscle (that powers joints). Cardiac muscle is responsible for pumping blood throughout the body
d) Tendon – (connective tissue) The soft tissue by which muscle attaches to bone. Tendons are somewhat flexible, but tough. When a tendon becomes inflamed, the condition is referred to as tendonitis.
e) Neuron – (Nervous tissue) A nerve cell that receives and sends electrical signals over long distances within the body. A neuron receives electrical input signals from sensory cells (called sensory neurons) and from other neurons. The neuron sends electrical output signals to muscle neurons (called motoneurons or motor neurons) and to other neurons. A neuron that simply signals another neuron is called an interneuron.
Any of the impulse-conducting cells that constitute the brain, spinal column, and nerves, consisting of a nucleated cell body with one or more dendrites and a single axon.
2. Describe two important internal conditions that must be maintained by homeostasis.
Homeostasis is the process used by the body to maintain a stable internal environment. Either negative feedback or positive feedback can be used in homeostasis.
In negative feedback, the body changes an internal condition back to its normal state; this is the most common way that the body regulates itself. Examples of negative feedback: (1) when blood pressure rises, the heart slows down; (2) when glucose levels in the blood are too high, the pancreas secretes insulin to stimulate the absorption of glucose and the conversion of glucose into glycogen.
In positive feedback, the body reacts to a change from the normal state by causing an even greater change. Examples of positive feedback: (1) when constrictions in the uterus push a baby into the birth canal, contractions in the uterus increase; (2) when a blood vessel is damaged, the vessel constricts and chemicals are released to plug and repair the hole.
Not involved in homeostasis
Do not continue long term
3. When your blood pressure increases, receptors in the blood vessel walls sense this change, and the signal is sent to the brain. The brain signals for the blood vessels to increase in diameter, thus lowering your blood pressure. Is this negative or positive feedback? Explain.
4. Explain what is meant by saying an animal is a homeotherm or a heterotherm. Are you a homeotherm or a heterotherm?
Homeotherm – an animal that maintains a constant body temp
Heterotherm – an animal that’s body temperature changes with the environment
Endotherm – organisms that use cellular respiration to raise and maintain body temp above air temp – birds and mammals
Ectotherm - organism that us external sorces to raise body temp and seek shade to cool.
Invertebrates, fishes, amphibians, reptiles
5. Describe one advantage and one disadvantage of endothermy.
6. Describe one advantage and one disadvantage of ectothermy.
7. Describe three specific mechanisms that an animal can use to regulate its body temperature, and state whether they are physical, behavioral, physiological, or cellular.
Physical mechanisms -